<PAGE>

                                 ADDENDUM III
                                      TO
                        SPRINT PCS MANAGEMENT AGREEMENT

MANAGER:            LOUISIANA UNWIRED, L.L.C.

SERVICE AREA:  BTA #302 MOBILE, AL
               BTA #450 Tuscaloosa, AL
               BTA #193 HOT SPRINGS, AR
               BTA #257 LITTLE ROCK, AR (CLARK, DALLAS, GRANT AND NEVADA
                    COUNTIES IN ARKANSAS ONLY)
               BTA #343 PENSACOLA, FL
               BTA #94 COLUMBUS, MS
               BTA #175 GREENVILLE, MS
               BTA #186 HATTIESBURG, MS
               BTA #210 JACKSON, MS
               BTA #246 LAUREL, MS
               BTA #269 MCCOMB, MS
               BTA #290 Memphis, TN (Grenada, Montgomery, Tallahatchie and
                    Yalobusha counties in Mississippi only)
               BTA #292 MERIDIAN, MS
               BTA #315 NATCHEZ, MS
               BTA #449 TUPELO, MS
               BTA #455 VICKSBURG, MS
               BTA #146 FLORENCE, AL
               BTA #158 GADSDEN, AL
               BTA #340 PANAMA CITY, FL
               BTA #439 TALLAHASSEE, FL (JACKSON COUNTY ONLY)
               BTA #108 DECATUR, AL
               BTA #154 FT. WALTON BEACH, FL
               BTA #17 ANNISTON, AL
               BTA #198 HUNTSVILLLE, AL
               BTA #415 SELMA, AL
               BTA #305 MONTGOMERY, AL
               BTA #459 BIRMINGHAM, AL (CHILTON, CULLMAN, TALLADEGA, COOSA AND
                    TALLAPOOSA COUNTIES ONLY)
               BTA #312 Nashville, TN (Marshall and Giles counties only)

     This Addendum III, dated as of October 12, 2000, contains certain
additional and supplemental terms and provisions to that certain Sprint PCS
Management Agreement entered into as of February 8, 1999, by the same parties as
this Addendum, which Management Agreement was further amended by that certain
Addendum I, dated February 8, 1999, and that certain Addendum II, dated  August
31, 1999 (as amended to date, the "MANAGEMENT AGREEMENT").  The terms and
provisions of this Addendum control, supersede and amend any conflicting terms
and provisions contained in the Management Agreement.   Except for express
modifications made in this Addendum III, the Management Agreement continues in
full force and effect.

     Capitalized terms used and not otherwise defined in this Addendum have the
meanings ascribed to them in the Management Agreement.  Section and Exhibit
references are to Sections and Exhibits of the Management Agreement unless
otherwise noted.

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     The Management Agreement is modified as follows:

     1.  DELETION OF SECTIONS FROM ADDENDUM II. Sections 3, 4 and 9 of Addendum
II are deleted in their entirety and of no effect from the date of this
Addendum.

     2.  LONG-DISTANCE PRICING.  (a) The first sentence of Section 3.4 is
deleted in its entirety and replaced with the following language:

               Prior to May 1, 2002, Manager must purchase from Sprint or Sprint
          PCS, at Sprint PCS' discretion, any additional circuits and long
          distance telephony services required for long distance telephony
          services used in the provision of Sprint PCS Products and Services in
          the Service Area served or currently planned to be served by Manager's
          existing switches in Jackson, Mississippi and Montgomery, Alabama.
          If, during the period from the date of this addendum until May 1,
          2002, Manager does not purchase or retain long-distance telephony
          services from Cameron Communications Corporation used in the provision
          of Sprint PCS Products and Services in the Service Area, Manager must
          purchase long-distance telephony services from Sprint or Sprint PCS,
          at Sprint PCS' discretion.

               On and after May 1, 2002, Manager must purchase, exclusively,
          from Sprint or Sprint PCS, at Sprint PCS' discretion, all long-
          distance telephony services used in the provision of Sprint PCS
          Products and Services in the entire Service Area.  This includes
          replacing any existing long distance service used in the provision of
          Sprint PCS Products and Services in the Service Area.

               Sprint PCS will bill Manager for the services used by Manager.
          Manager will be charged the same price for such long-distance service
          as Sprint PCS is charged by Sprint plus an additional administrative
          fee to cover Sprint PCS' processing costs.

               Manager may not resell the long-distance telephony services
          acquired from Sprint under this Section 3.4.

; and the last three sentences in Section 3.4 are deleted in their entirety.

     (b)  Section 3.7 is modified by adding the following language: "(other than
backhaul services relating to national platform and IT application connections,
which Manager must purchase from Sprint if Manager is a Type I or Type II
affiliate as described on Exhibit 2.1.1)" both between (A) "Service Area
Network" and "if Manager decides to use" in the first sentence of the first
paragraph and (B) "for these services" and "and the agreement was not made" in
the first sentence of the second paragraph.

     (c)  "Long-distance telephony services used in the provision of Sprint PCS
Products and Services" means services needed to provide long-distance telephony
service to users of the Sprint PCS Network, but not services to connect the
Service Area Network with the national platforms used by Sprint PCS to provide
services to Manager under the agreement and/or the Services Agreement.

     (d)  If, after May 1, 2002, Manager delivers to Sprint PCS a copy of a
competitive bid from a long-distance telephony service provider who meets
Sprint's network reliability and voice quality standards in force at the time
Sprint receives the bid proposal (certified by the chief executive officer of

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Manager as an accurate and complete description of such bid) to provide long-
distance services to Manager, and such bid is for a period not less than two
years and includes transport charges that are at least 10% less than the
transport charges and administrative fee charged by Sprint, Manager may purchase
long-distance services until the underlying contract resulting from the
certified bid terminates, at which time the language in (a) above governs.

     3.  CONVERSION TO TYPE II AFFILIATE. Manager will complete the conversion
of the Service Area Network from "Type III" (i.e., where Manager designates
Option #3 on Exhibit 2.1.2 to the Services Agreement) to "Type II" (i.e., where
Manager designates Option #2 on Exhibit 2.1.2 to the Services Agreement) no
later than June 30, 2001.  Sprint PCS will use good faith efforts to assist
Manager with its conversion, which assistance will include meeting deadlines
critical to completing conversion by June 30, 2001. If Manager is unable to meet
the June 30, 2001 conversion date because of non-performance by Sprint PCS,
Sprint PCS will extend the conversion date.

     If it is determined, after commercially reasonable efforts by Sprint PCS
and Manager, that the post-pay subscribers supported on Manager's systems can
only be converted to Type II services by June 30, 2001 by changing their phone
numbers (the NPA-NXX-XXXXs assigned to subscribers in the Manager's Service
Area), Sprint PCS will allow Manager to continue to support such subscribers on
Manager's systems after conversion, but the parties agree that they will
continue to use commercially reasonable efforts to convert all post-pay
customers to Type II services as soon as possible. In no event will Sprint PCS
require Manager to terminate the service of such post-pay subscribers.

     Sprint PCS will pay for the actual costs it incurs to input Manager's
customer information into plans then supported by Sprint PCS' billing and other
systems. Manager will pay for the actual costs it incurs to migrate customer
information from its billing system to Sprint PCS' billing system. Manager is
responsible for establishing and maintaining a Type II Affiliation in a manner
consistent with the way Other Managers establish and maintain Type II
Affiliations in the Sprint PCS Affiliations Program.

     Furthermore, Sprint PCS Products and Services offered by the Manager that
are not supported by Sprint PCS billing and other systems will not be added into
Sprint PCS' billing or other systems without Sprint PCS' approval, at its sole
discretion.  If Sprint PCS approves the addition of a Sprint PCS product or
service offered by the Manager that is not supported by Sprint PCS billing and
other systems at the point in time when the Manager requests addition of such
product and service, Manager will pay all costs associated with the development
and implementation of the modifications to Sprint PCS' billing and other systems
that are required to add such plan, product or service.

     4.   REVISED DESIGNATION OF SELECTED SERVICES.  Exhibit 2.1.2 attached to
this addendum supersedes and replaces in its entirety Exhibit 2.1.2 previously
agreed to.

     5.   BILLING SERVICE FEE. From the date Manager's conversion to a Type II
is complete until the earlier to occur of (i) December 31, 2002 or (ii) the date
on which Sprint PCS no longer uses the billing platform currently in use by it,
Sprint PCS will charge Manager for billing pre-pay customers the lesser of (x)
the same service fee it charges Manager for post-pay customers or (y) the fees
charged to Other Managers for prepaid billing services based on standard
services provided to such Other Managers under the Services Agreement.

     6.   INTER AREA SERVICE FEE.  Inter area service fees will apply in
accordance with the Management Agreement, except that, the current inter area
service fee of "CONFIDENTIAL INFORMATION OMITTED AND FILED SEPARATELY WITH THE
SECURITIES AND EXCHANGE COMMISSION" cents will not decrease for transactions
between Sprint PCS and Manager (e.g., does not apply to transactions

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between Manager and Other Managers) until December 31, 2002.

     7.   Chatpak. (a) Upon the later to occur of (i) completion of Manager's
Type II conversion or (ii) Sprint PCS offers a prepaid product (the "Prepaid
Change Date"), Manager will cease to promote and sell all prepaid products and
services that utilize Manager's billing platform, but Manager will continue to
support such prepaid products and services for customers who are on its
Manager's prepaid platform as of the Prepaid Change Date and were acquired on or
before the Prepaid Change Date.

     (b) The terms and provisions in this paragraph 7 govern any conflicting
terms and provisions in paragraph 3.

     8.   Resolution of Compliance Issues.  Manager will resolve all material
compliance issues by the respective deadlines set forth on Exhibit B to this
Addendum.

     9.   Manager Acquisitions.  If Manager acquires control of an Other Manager
with a Type III system configuration or its Operating Assets, Manager will work
with Sprint PCS to convert such acquired system to a Type II configuration
within 6 months of the close of the transaction subject to Sprint PCS'
cooperation and assistance.

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     IN WITNESS WHEREOF, the parties hereto have caused this Addendum to be
executed as of the date first above written.

                                 LOUISIANA UNWIRED, LLC


                                 By:
                                    ---------------------------------
                                    Name:
                                         ----------------------------
                                    Title:
                                          ---------------------------

                                 SPRINTCOM, INC.


                                 By:
                                    ---------------------------------
                                    Thomas E. Mateer
                                    Vice President - Affiliations

                                 SPRINT SPECTRUM L.P.


                                 By:
                                    ---------------------------------
                                    Thomas E. Mateer
                                    Vice President - Affiliations

                                 WIRELESSCO, L.P.


                                 By:
                                    ---------------------------------
                                    Thomas E. Mateer
                                    Vice President - Affiliations

                                 SPRINT COMMUNICATIONS COMPANY L.P.


                                 By:
                                    ---------------------------------
                                    Name:
                                         ----------------------------
                                    Title:
                                          ---------------------------

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