<PAGE>

                       MCI WORLDCOM NETWORK SERVICES, INC.

                      CLASSIC/TRANSCEND-TM- SWITCHED SERVICES

                                 AMENDMENT NO. 4

         This Amendment No. 4 is made as of the 21  day of December , 1999,
by and between Logix Communications Corporation ("CUSTOMER") and MCI
WORLDCOM Network Services, Inc. (successor-in-interest to WorldCom Network
Services, Inc.), a Delaware corporation ("MCI WORLDCOM") to that certain
CLASSIC/TRANSCEND-TM- Telecommunications Services Agreement (the "TSA") dated
June, 1998, by and between Customer and MCI WorldCom, including those certain
Program Enrollment Terms, any applicable Attachments and that certain
Amendment No. 1 dated January 1, 1999, that certain Amendment No. 2 dated
October 1, 1999, and that certain Amendment No. 3 dated January 1, 2000. In
the event of any conflict between the terms of the TSA, the PET, any
applicable Attachments, Amendment No. 1, Amendment No. 2 and Amendment No. 3
and the terms of this Amendment No. 4, the terms of this Amendment No. 4
shall control. The TSA along with the PET, all applicable Attachments,
Amendment No. 1, Amendment No. 2, Amendment No. 3 and this Amendment No. 4
shall collectively be referred to as the "AGREEMENT".

         The parties agree for good and valuable consideration, intending
legally to be bound, as follows:

1.       SPECIAL RATES.

         (A)      Commencing with Customer's December, 1999 billing period
         (i.e. January, 1999 invoice) and continuing through the end of
         the Service Term, Customer's Interstate CALLING CARD Service
         charge described in Section 1. of that certain Attachment for
         CALLING CARD Service dated concurrently herewith will be
         $0.0900.

         (B)      Commencing with Customer's December, 1999 billing period
         (i.e., January, 1999 invoice) and continuing through the end
         of the Service Term, the parties agree to substitute the Rate
         Schedule described in Subsection 1.(1)(a) of that certain
         Attachment for DEBIT CARD Service dated concurrently herewith
         to read in its entirety as follows:

                  (a)      If Customer's order is for less than 200,000 Units:
                           $0.1000.

2.       OTHER TERMS AND CONDITIONS.  Except as specifically amended or
         modified herein, the terms and conditions of the Agreement
         will remain in full force and effect throughout the applicable
         Service Term and any extensions thereof.


                                 Page 1 of 2
                                 CONFIDENTIAL

<PAGE>

         IN WITNESS WHEREOF the parties have entered into this
Amendment No. 4 on the date first written above.

MCI WORLDCOM NETWORK                    LOGIX COMMUNICATIONS CORPORATION
SERVICES, INC.

By: /s/ James Foran                     By: /s/ Albert H. Pharis, Jr.
   ------------------------------          -----------------------------------
Print Name: James Foran                 Print Name: /s/ Albert H. Pharis,  Jr.
           ----------------------                  ---------------------------
Title: Regional Sales Director          Title: CEO
      ---------------------------             -----------------------------



                                 Page 2 of 2
                                 CONFIDENTIAL




<PAGE>

                        WORLDCOM NETWORK SERVICES, INC.

                      ATTACHMENT FOR CALLING CARD SERVICE

         This Attachment for CALLING CARD SERVICE is made by and between
Logix Communications Corporation ("CUSTOMER") and WorldCom Network Services,
Inc. ("MCI WORLDCOM") and is a part of their Telecommunications Services
Agreement for Switched Services. Capitalized terms not defined herein shall
have the meaning ascribed to them in the TSA, the PET, the applicable
Attachment(s) or the Tariff (as defined below), whichever is applicable.
NOTE: ANY MODIFICATIONS, ADDITIONS OR DELETIONS FROM THIS ATTACHMENT WILL NOT
BE EFFECTIVE UNLESS SPECIFICALLY SET FORTH IN THE PET.

                  During the Service Term of the Agreement, MCI WorldCom will
provide "CALLING CARD SERVICE" which is accessed only by dialing the unique
toll free access number assigned by MCI WorldCom to Customer. With respect to
Domestic Interstate and International CALLING CARD Service, this Attachment
incorporates by reference the terms of MCI Tariff FCC No. 1 (the "Tariff"),
which may be modified from time to time by MCI WorldCom in accordance with
law and thereby affect the Services furnished Customer hereunder, except that
the terms and conditions contained in the TSA, the PET or this Attachment
shall supplement or, to the extent inconsistent, supersede the Tariff terms
and conditions. For purposes of this Attachment, references to "MCI FEATURE
CARD Service (Option T)" or "Connections Card Service" will be deemed to
refer to "CALLING CARD Service".

I.       CALLING CARD SERVICE CHARGES.

         For purposes of this Attachment, Customer's "Switched Services
         Revenue" will be comprised of (i) Customer's gross (i.e., prior to
         the application of discounts) measured and per call CALLING CARD
         Service charges described below (i.e.,interstate, intrastate and
         international), (ii) Customer's Calling Card Service Surcharges
         described below, and (iii) Customer's Calling Card Feature Service
         charges described below.

<TABLE>
<CAPTION>

         JURISDICTION                                           RATE PER MINUTE*
         --------------------------------------------------------------------------------
         <S>                                                    <C>
         INTERSTATE
         Within the 48 contiguous United States, Alaska,        $0.1300 per minute
           Hawaii, Puerto Rico and the United States Virgin
           Islands
         --------------------------------------------------------------------------------
         INTRASTATE                                             $0.1300 per minute
         --------------------------------------------------------------------------------
         INTERNATIONAL                                          SEE Section C.3.07312 of the
                                                                Tariff and Section 3.0734 of
                                                                the Tariff with respect to calls
                                                                from one International location
                                                                to another.
         --------------------------------------------------------------------------------
</TABLE>

         * Notes: If Customer's Minimum Revenue Commitment described in the PET
         is less than $10,000, Customer's Interstate rate will be $0.25 per
         minute and will not be subject to any discount.

                                 Page 1 of 5
                                 CONFIDENTIAL
<PAGE>

II.      CREDITS/DISCOUNTS.

         (A)      During each month of the Service Term, Customer shall
         receive a NonInternational usage credit (the "DOMESTIC CREDIT")
         calculated by multiplying the applicable percentage shown below
         based on Customer's Monthly Revenue (as defined in the PET) times
         Customer's domestic interstate and intrastate usage charges for
         CALLING CARD Service (exclusive of monthly recurring charges, taxes,
         surcharges, installation charges, CALLING CARD Service surcharges,
         Directory Assistance charges, charges for local access/egress
         services or facilities, and enhanced feature charges associated with
         CALLING CARD Service). Customer shall also receive an International
         usage credit (the "INTERNATIONAL CREDIT") calculated by multiplying
         seventy percent (70%) times Customer's International usage charges
         for CALLING CARD Service (exclusive of monthly recurring charges,
         taxes, surcharges, installation charges, CALLING CARD Service
         surcharges, Directory Assistance charges, charges for local
         access/egress services or facilities, and enhanced feature charges
         associated with CALLING CARD Service.

<TABLE>
<CAPTION>

                                       Non-International
         Monthly Revenue                    Discount
                                            --------
         <S>                           <C>
         $ 10,000 - $ 49,999                0.0%
         $ 50,000 - $ 99,999                3.5%
         $100,000 - $249,999                5.0%
         $250,000 - $499,999                6.5%
         $500,000 - $749,999                10.0%
         $750,000 - $999,999                12.5%
             $1,000,000+                    15.0%
</TABLE>

         (B)      The Domestic Credit and the International Credit described
         above are in lieu of any Tariff discounts including, without
         limitation, discounts for MCI Feature Card Service available under
         MCI VIP, MCI VIP Plus, MCI MOD and MCI CAS or MCI CAS PLUS Service.

III.     CALLING CARD SERVICE SURCHARGES.

         (A)      The following CALLING CARD Service surcharges shall be
         charged according to the following schedule:

<TABLE>
<CAPTION>
                                                                                       DIRECT
                   FROM                                       TO                        DIAL
         --------------------------                  --------------------------        ------
         <S>                                         <C>                               <C>
         Within the 48 contiguous                    U.S. (Interstate)                  $0.00
         United States ("U.S.")
         --------------------------                  --------------------------        ------
         U.S.                                        U.S. Intrastate                    $0.25
         --------------------------                  --------------------------        ------
         Alaska, Hawaii, Puerto Rico                 U.S.                               $0.25
         and United States Virgin
         Islands
         --------------------------                  --------------------------        ------
         U.S.,   Alaska,   Hawaii,                   Alaska, Hawaii, Puerto Rico        $0.25
         Puerto  Rico and  United                    and  United  States Virgin
         States Virgin Islands                       Islands
         --------------------------                  --------------------------        ------
         U.S.,   Alaska,   Hawaii,                   Canada                             $0.25
         Puerto  Rico and  United
         States Virgin Islands
         --------------------------                  --------------------------        ------


                                 Page 2 of 5
                                 CONFIDENTIAL
<PAGE>

         --------------------------                  --------------------------        ------
         U.S., Alaska, Hawaii,                          International locations         $1.25
         Puerto Rico and United
         States Virgin Islands
         --------------------------                  --------------------------        ------
         Canada                                         Alaska, Hawaii, Puerto Rico     $1.00
                                                        and  United States Virgin
                                                        Islands
         --------------------------                  --------------------------        ------
         Canada                                         International locations         $1.25
         --------------------------                  --------------------------        ------
         U.S. (Payphone)                                Any location                    $0.30
         --------------------------                  --------------------------        ------

</TABLE>

IV.      FULFILLMENT.

         If Customer elects to use MCI WorldCom for fulfillment, Customer
         shall pay MCI WorldCom the fulfillment charges associated with
         Customer's usage of CALLING CARD Service, as determined by MCI
         WorldCom.

V.       SET UP CHARGES.

         Customer agrees to pay $600 for every instance of special branding
         (i.e., greeting and/or closing) requested by Customer in connection
         with CALLING CARD Service.

VI.      FRAUD DETECTION PROCEDURES.

         Customer shall be responsible for any and all fraud associated with its
         usage of CALLING CARD Service, except as set forth below:

                  (1)      All calling card calls will be validated by MCI
                  WorldCom to permit only those calls authorized or
                  facilitated by Customer or legitimate card holders. MCI
                  WorldCom will, at the direction of Customer, preclude
                  all calls utilizing expired or terminated calling card
                  numbers compared against an authorized list provided by
                  Customer and MCI WorldCom will be responsible for all
                  fraudulent use, unauthorized use, misuse, or abuse of
                  calling cards occurring after MCI WorldCom receives
                  actual notice of the expiration or termination of a
                  calling card or receives specifically detailed written
                  notification concerning any card which has been lost,
                  stolen, compromised or which Customer has reason to
                  believe is or may be used fraudulently.

                  (2)      In addition, all CALLING CARD Service calls will
                  be monitored by MCI WorldCom for misuse on a twenty
                  four (24) hour a day, seven (7) days a week basis. MCI
                  WorldCom shall establish fraud prevention, detection
                  and minimization procedures so that fraudulent use
                  arising from lost or stolen calling cards and potential
                  disruption to authorized card holders will be
                  minimized.

                  (3)      MCI WorldCom will not hold the Customer
                  responsible for "Service Fraud" (as defined herein)
                  associated with the unauthorized use of an MCI WorldCom
                  CALLING CARD. For purposes of this Attachment, "SERVICE
                  FRAUD" shall consist of unauthorized use of an MCI
                  WorldCom CALLING CARD following the involuntary theft
                  or loss of a card which was not intentionally
                  facilitated or authorized (either explicitly or
                  implicitly) by Customer or an authorized user. Service
                  Fraud often follows the theft of a wallet, purse or
                  briefcase, or sometimes is the result of "shoulder
                  surfing" (thieves observing/recording authorization
                  codes) which occurs at payphones located in airports,
                  bus terminals, train stations and the


                                 Page 3 of 5
                                 CONFIDENTIAL
<PAGE>

                  like. MCI WorldCom shall not be responsible for losses caused
                  by fraudulent information submitted by a card holder in
                  subscribing for calling card services or for usage which was
                  intentionally facilitated or authorized (either explicitly or
                  implicitly) by an authorized user.

                  (4) In the event MCI WorldCom is unable to contact Customer of
                  suspected abuse of the CALLING CARD Service, in order to
                  minimize potential abuse, MCI WprldCom may deactivate any
                  calling card which has exceeded established fraud detection
                  parameters or which MCI WorldCom has reason to believe is or
                  may be used fraudulently. In such event MCI WorldCom will have
                  no liability to Customer or any End User in connection with
                  such deactivation or failure to deactivate such calling card.

VII.     TARIFFED FEATURE SERVICES.

         (A)      Customer agrees to pay the rates set forth in Subsection
         C.3.21 of the Tariff for all Tariffed Feature Services (i.e.,
         Conference Calling and Operator Services).

         (B)      In lieu of any discounts set forth in the Tariff, Customer
         will be entitled to the following applicable incremental discounts
         on Customer's usage of Tariffed Feature Services (i.e., conference
         calling) as determined by Customer's Tariffed Feature Services
         Monthly Usage (as defined in Subsection (D) below).

<TABLE>
<CAPTION>

             Tariffed Feature
         Services Monthly Usage           Discount
         ----------------------           --------
         <S>                              <C>
         $      0 - $    999                3.0%
         $  1,000 - $ 19,999                6.0%
         $ 20,000 - $ 49,999                6.5%
         $ 50,000 - $ 99,999                7.0%
         $100,000 - $249,999                7.5%
         $250,000 - $374,999                8.0%
             $375,000 +             8.5%

</TABLE>

         (C)      The discounts described in Subparagraph VII.(B) above shall
         apply only to Customer's usage of Tariffed Feature Services provided
         pursuant to MCI WorldCom is standard rates, terms and conditions for
         such services, but not to charges for installation, taxes or
         surcharges, and charges for local access/egress services or
         facilities associated with Tariffed Feature Services.

         (D)      "TARIFFED FEATURE SERVICES MONTHLY USAGE" shall mean
         Customer's monthly combined recurring and usage charges for Tariffed
         Feature Services at standard pricing but not including taxes (and
         gross receipts taxes), surcharges, and any charges for services
         provided under the Tariff.

VIII.    NON-TARIFFED FEATURE SERVICES.

         (A)      Customer agrees to pay standard rates for all Non-
         Tariffed Feature Services (i.e., Message Store and Forward,
         Flexible Routing for Voice Mail, Voice News Network and
         Speed Dialing).


                                 Page 4 of 5
                                 CONFIDENTIAL
<PAGE>

         (B)      Customer will be entitled to the following applicable
         incremental discounts on Customer's usage of non-tariffed CALLING CARD
         Services (Conference Calling, Message Store and Forward) as determined
         by Customer's Non-Tariffed Feature Services Monthly Usage (as defined
         in Subsection (D) below):

<TABLE>
<CAPTION>

         Non-Tariffed Feature
         Services Monthly Usage           Discount
         ----------------------           --------
         <S>                              <C>
         $      0 - $    999                3.0%
         $  1,000 - $ 19,999                6.0%
         $ 20,000 - $ 49,999                6.5%
         $ 50,000 - $ 99,999                7.0%
         $100,000 - $249,999                7.5%
         $250,000 - $374,999                8.0%
             $375,000 +             8.5%

</TABLE>

         (C)      The discounts described in Subparagraph (B) above shall
         apply only to Customer's Calling Card usage of non-tariffed Feature
         Services provided pursuant to MCI WorldCom is standard rates, terms
         and conditions for such services, but not to charges for
         installation, taxes or surcharges, and charges for local
         access/egress services or facilities associated with non-tariffed
         Feature Services.

         (D)      "NON-TARIFFED FEATURE SERVICES MONTHLY USAGE" shall mean
         Customer's monthly combined recurring and usage charges for
         non-tariffed Feature Services at standard pricing but not including
         taxes (and gross receipts taxes), surcharges, and any charges for
         services provided under the Tariff.

         IN WITNESS WHEREOF, authorized parties on behalf of their
respective entities have initialed this Attachment for CALLING
CARD Service as of the date shown below.


LOGIX COMMUNICATIONS CORPORATION            WORLDCOM NETWORK SERVICES, INC.

Customer's Initials /s/ AHP                   MCI WorldCom's Initials /s/ JF
                   ----------                                      --------
Date:  12-17-99                             Date:  12-21-99
     ------------------------                    --------------------------


                                 Page 5 of 5
                                 CONFIDENTIAL
<PAGE>

                         WORLDCOM NETWORK SERVICES, INC.
                        ATTACHMENT FOR DEBIT CARD SERVICE


         This Attachment for DEBIT CARD Service is made by and between LOGIX
COMMUNICATIONS CORPORATION ("CUSTOMER") and WorldCom Network ervices, Inc.
("MCI WORLDCOM") and is a part of their Telecommunications Services Agreement
for Switched Services. Capitalized terms not defined herein shall have the
meaning ascribed to them in the TSA, the PET, the applicable Attachment(s) or
the Tariff (as defined below), whichever is applicable. NOTE: ANY
MODIFICATIONS, ADDITIONS OR DELETIONS FROM THIS ATTACHMENT WILL NOT BE
EFFECTIVE UNLESS SPECIFICALLY SET FORTH IN THE PET.

         During the Service Term of the Agreement, MCI WorldCom will provide
"DEBIT CARD Service" pursuant to which Customer shall utilize MCI WorldCom for
the debit card platform and transport of Customer's domestic interstate
termination of debit card traffic. With respect to Domestic Interstate and
International DEBIT CARD Service, this Attachment incorporates by reference the
terms of MCI Tariff FCC No. 1 (the "TARIFF'), which may be modified from time to
time by MCI WorldCom in accordance with law and thereby affect the Services
furnished Customer hereunder, except that the terms and conditions contained in
the TSA, the PET or this Attachment shall supplement or, to the extent
inconsistent, supersede the Tariff terms and conditions. With respect to
Intrastate DEBIT CARD Service, this Attachment incorporates by reference each
applicable state tariff filed by MCI WorldCom, which may be modified from time
to time by MCI WorldCom, and thereby affect the Services furnished. For purposes
of this Attachment, with respect to domestic calls, a "DEBIT CARD UNIT" shall
equal one minute of usage.

l.       DEBIT CARD SERVICE CHARGES.

         The rates shown below shall include access to the MCI WorldCom debit
         card platform, transport, order entry and debit card activation.
         Customer shall pay the following rate per Debit Card Unit, as
         determined by the number of Debit Card Units purchased by Customer
         in each individual purchase, and not determined by the aggregate
         number of Debit Card Units purchased throughout the Service Term.
         Customer will not be charged for incomplete calls (i.e., calls not
         answered at the ultimate destination).

         NOTE: The rates listed below do not include operator services or
         customer service for Customer's End Users. If Customer chooses to
         purchase operator services, pursuant to the terms and conditions of
         the Tariff, an additional $0.01 per DEBIT CARD UNIT shall be added
         to the rates below.

         (1)      Customer's rate per Unit will be as follows based on
         Customer's Minimum Revenue Commitment (as described in the PET) and
         the number of Units per Order:

                  (a)      If Customer's order is for less than 200,000 Units:


                                 Page 1 of 4
                                 CONFIDENTIAL


<PAGE>

<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------
                           <S>                                <C>
                           $      0 - $ 49,999                $0.1150
                           $ 50,000 - $ 99,999                $0.1110
                           $100,000 - $249,999                $0.1093
                           $250,000 - $499,999                $0.1075
                           $500,000 - $749,999                $0.1035
                           $750,000 - $999,999                $0.1006
                              $1,000,000+                     $0.0978
</TABLE>


                  (b)      If Customer's order is for between 200,000 and
                  399,999 Units:


<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------
                           <S>                                <C>
                           $      0 - $ 49,999                $0.1139
                           $ 50,000 - $ 99,999                $0.1098
                           $100,000 - $249,999                $0.1081
                           $250,000 - $499,999                $0.1064
                           $500,000 - $749,999                $0.1024
                           $750,000 - $999,999                $0.0995
                              $1,000,000+                     $0.0966
</TABLE>


                  (c)      If Customer's order is for between 400,000 and
                  599,999 Units:


<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------
                           <S>                                <C>
                           $      0 - $ 49,999                $0.1116
                           $ 50,000 - $ 99,999                $0.1087
                           $100,000 - $249,999                $0.1070
                           $250,000 - $499,999                $0.1052
                           $500,000 - $749,999                $0.1012
                           $750,000 - $999,999                $0.0983
                                $1,000,000+                   $0.0955

</TABLE>

                  (d)      If Customer's order is for between 600,000 and
                  799,999 Units:


<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------
                           <S>                                <C>
                           $      0 - $ 49,999                $0.1082
                           $ 50,000 - $ 99,999                $0.1075
                           $100,000 - $249,999                $0.1058
                           $250,000 - $499,999                $0.1041
                           $500,000 - $749,999                $0.1001
                           $750,000 - $999,999                $0.0972.
                               $1,000,000+                    $0.0943

</TABLE>

                  (e)      If Customer's order is for between 800,000 and
                  999,999 Units:


<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------


                                 Page 2 of 4
                                 CONFIDENTIAL

<PAGE>



                           <S>                                <C>
                           $      0 - $ 49,999                $0.1039
                           $ 50,000 - $ 99,999                $0.1064
                           $100,000 - $249,999                $0.1047
                           $250,000 - $499,999                $0.1029
                           $500,000 - $749,999                $0.0989
                           $750,000 - $999,999                $0.0960
                               $1,000,000+                    $0.0932
</TABLE>
                  (f)      If Customer's order is equal to or greater than
                  1,000,000 Units:

<TABLE>
<CAPTION>

                           Minimum Revenue Commitment          Rate
                           --------------------------         -------
                           <S>                                <C>
                           $      0 - $ 49,999                $0.0987
                           $ 50,000 - $ 99,999                $0.1052
                           $100,000 - $249,999                $0.1035
                           $250,000 - $499,999                $0.1018
                           $500,000 - $749,999                $0.0978
                           $750,000 - $999,999                $0.0949
                               $1,000,000+                    $0.0920

</TABLE>

         (2)      Customer shall order a minimum of $10,000 in Debit Card
         Units per order. Notwithstanding anything to the contrary contained
         in the Agreement, Customer shall prepay MCI WorldCom for all orders
         under this Attachment before MCI WorldCom will be obligated to
         accept such orders.

         (3)      Customer may order, at no cost to Customer, one primary
         identification number (PIN) for every five (5) Debit Card Units
         purchased. Further, Customer agrees to pay a set-up charge of $0.06
         per PIN for every PIN ordered by Customer in excess of the ration of
         one PIN per five Debit Card Units as described herein.

         (4)      Customer's Debit Card Units will be reduced by the Debit
         Card Units utilized by completed calls (calls that are answered at
         the ultimate destination).  MCI WorldCom shall determine the number
         of Debit Card Units necessary to receive one minute of international
         calling ("DEPLETION SCHEDULE"). The current Depletion Schedule is
         shown on Schedule DC-A ("DEPLETION SCHEDULE"). MCI WorldCom retains
         the right to develop and implement (upon thirty (30) day prior
         notice) a separate and distinct Depletion Schedule which shall
         supersede the Depletion Schedule. Customer shall receive no refund
         or reimbursement for unused Debit Card Units at any time including
         upon the expiration, cancellation or earlier termination of this
         Agreement.

         (5)      In addition to the above rates, Customer shall pay an
         additional Six Hundred Dollar ($600.00) charge for each customized
         script identifying Customer to its End Users.

         (6)      Customer shall be solely responsible for all card
         fulfillment and end user customer service.

         (7)      Customer shall not include MCI WorldCom is name or logo on
         any Customer debit card.

         (8)      For purposes of this Attachment, Customer's "SWITCHED
         SERVICES REVENUE" will be comprised of Customer's unit charges
         described in Subpart (1) above.

                                Page 3 of 4
                                CONFIDENTIAL

<PAGE>

         (9)      Customer's Debit Card Units will be reduced by two (2) Units
         (the "DEPLETION RATE") for every completed Debit Card call originated
         from a payphone, MCI WorldCom reserves the right, upon at least
         thirty (30) days' prior written notice, to modify the Depletion Rate
         for completed calls originated from payphones.

         IN WITNESS WHEREOF, authorized parties on behalf of their respective
entities have initialed this Attachment for DEBIT CARD Service as of the date
shown below.



Logix Communications Corporation            WORLDCOM NETWORK SERVICES, INC.

Customer's Initials /s/ AHP                 MCI WorldCom's Initials /s/ JF
                   -------------                                   --------
Date:  12-17-99                             Date: 12-21-99
     ---------------------------                 --------------------------


                                Page 4 of 4
                                CONFIDENTIAL