<PAGE>

Exhibit 4.3                                  This document constitutes part of a
-----------                                  prospectus covering securities that
                                             have been registered under the
                                             Securities Act of 1933.









                             AMENDED AND RESTATED
                      DIAL-THRU INTERNATIONAL CORPORATION
                               STOCK OPTION PLAN
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<S>                                                        <C>
                                   ARTICLE 1

                        DEFINITIONS AND INTERPRETATION

1.1  Definitions.........................................  1
1.2  Choice of Law.......................................  2
1.3  Headings............................................  2

                                  ARTICLE II
                           PURPOSE AND PARTICIPATION

2.1  Purpose.............................................  2
2.2  Participation.......................................  3
2.3  Notification of Award...............................  3
2.4  Copy of Plan........................................  3
2.5  Limitation..........................................  3

                                  ARTICLE III
                        TERMS AND CONDITIONS OF OPTIONS

3.1  Board to Allot Shares...............................  3
3.2  Number of Shares....................................  4
3.3  Term of Option......................................  4
3.4  Termination of Option...............................  4
3.5  Exercise Price......................................  5
3.6  Assignment of Options...............................  6
3.7  Adjustments.........................................  6

                                  ARTICLE IV
                              EXERCISE OF OPTION

4.1  Exercise of Option..................................  6
4.2  Issue of Share Certificates.........................  7
4.3  Condition of Issue..................................  7

                                   ARTICLE V
                                ADMINISTRATION

5.1  Administration......................................  7
5.2  Interpretation......................................  8

                                  ARTICLE VI
                           AMENDMENT AND TERMINATION

6.1  Prospective Amendment...............................  8
6.2  Retrospective Amendment.............................  8
6.3  Termination.........................................  8
6.4  Agreement...........................................  9
</TABLE>
<PAGE>

                               STOCK OPTION PLAN

                                   ARTICLE I
                        DEFINITIONS AND INTERPRETATION
                        ------------------------------

1.1  Definitions

As used herein, unless anything in the subject matter or context is inconsistent
therewith, the following terms shall have the meanings set forth below:

a)   "Administrator" means, initially, the secretary of the Issuer and
     thereafter shall mean such director or other senior officer or employee of
     the Issuer as may be designated as Administrator by the Board from time to
     time;

b)   "Award Date" means the date on which the Board awards a particular Option;

c)   "Board" means the board of directors of the Issuer;

d)   "Director" means any individual holding the office of director of the
     Issuer;

e)   "Employee" means any individual regularly employed on a full-time or part-
     time basis by the Issuer (or any wholly-owned, direct or indirect
     subsidiary of the Issuer) or other persons who either perform services for
     the Issuer (or any wholly-owned, direct or indirect subsidiary of the
     Issuer) on an ongoing basis or who have provided, or are expected to
     provide, a service of value to the Issuer (or any wholly-owned, direct or
     indirect, subsidiary of the Issuer);

f)   "Exercise Notice" means the notice respecting the exercise of an Option, in
     the form set out as Schedule "B" hereto, duly executed by the Option
     Holder;

g)   "Exercise Period" means the period during which a particular Option may be
     exercised and is the period from and including the Award Date through to
     and including the Expiry Date;

h)   "Exercise Price" means the price at which an Option may be exercised as
     determined in accordance with paragraph 3.5;

i)   "Expiry Date" means the date determined in accordance with paragraph 3.3
     and after which a particular Option cannot be exercised;

j)   "Issuer" means Dial-Thru International Corporation, a Delaware corporation,
     formerly known as ARDIS Telecom & Technologies, Inc., successor by merger
     to Canmax, Inc.

k)   "Market Value" means the closing price of the Issuer's Shares on the date
     the Issuer's shared traded through the facilities of NASDAQ SmallCap Market
     or OTC Bulletin Board immediately preceding a date of determination, unless
     the Shares did not trade through the facilities of NASDAQ SmallCap Market
     or OTC Bulletin Board on that day in which case it is the closing price of
     the Issuer's Shares the last day they traded through the facilities of
     NASDAQ SmallCap Market or OTC Bulletin Board;

1)   "Option" means an option to acquire Shares, awarded to a Director or
     Employee pursuant to the Plan;

m)   "Option Certificate" means the certificate evidencing an Option;

n)   "Option Holder" means a Director or Employee, or former Director or
     Employee, who holds an unexercised and unexpired Option or, where
     applicable, the Personal Representative of such person;

o)   "Plan" means this Amended and Restated Dial-Thru International Corporation
     Stock Option Plan;
<PAGE>

p)  "Personal Representative" means:

     i.   in the case of a deceased Option holder, the executor or administrator
          of the deceased duly appointed by a court or public authority having
          jurisdiction to do so; and

     ii.  in the case of an Option Holder who for any reason is unable to manage
          his or her affairs, the person entitled by law to act on behalf of
          such Option Holder; and

q)   "Sale Transaction" means any of the following events:

     i.   any consolidation or merger of the Issuer in which the Issuer is not
          the continuing or surviving company or pursuant to which shares of
          common stock of Issuer would be converted into cash, securities or
          other property, other than a merger of the Issuer in which the holders
          of the common stock of the Issuer immediately prior to the merger have
          the same proportion of ownership of common stock of the surviving
          company immediately after the merger or which would result in the
          voting securities of the company outstanding immediately prior thereto
          continuing to represent (either by remaining outstanding or by being
          converted into voting securities of the surviving entity) at least
          fifty percent of the total voting power represented by the voting
          securities of the Issuer or such surviving entity outstanding
          immediately following such merger or consolidation; or

     ii.  any sale, lease, exchange or other transfer (in one transaction or a
          series of related transactions) of in excess of fifty percent of the
          assets of the Issuer.

r)   "Share" or "Shares" means, as the case may be, one or more common shares,
     par value $.001 per share, in the capital of the Issuer.

1.2  Choice of Law
     -------------

The Plan is established under and the provisions of the Plan shall be
interpreted and construed in accordance with the laws of the State of Delaware.

1.3  Headings
     --------

The headings used herein are for convenience only and are not to affect the
interpretation of the Plan.

                                  ARTICLE II
                                  ----------
                           PURPOSE AND PARTICIPATION
                           -------------------------

2.1  Purpose
     -------

The purpose of the Plan is to provide the Issuer with a share-related mechanism
to attract, retain and motivate qualified Directors and Employees, to reward
such of those Directors and

                                       2
<PAGE>

Employees as may be awarded Options under the Plan by the Board from time to
time for their contributions toward the long term goals of the Issuer and to
enable and encourage such Directors and Employees to acquire Shares as long term
investments.

2.2  Participation
     -------------

The Board shall, from time to time, in its sole discretion determine those
Directors and Employees, if any, to whom Options are to be awarded.  If the
Board elects to award an Option to a Director, the Board shall, in its sole
discretion but subject to paragraph 3.2, determine the number of Shares to be
acquired on the exercise of such Option.  If the Board elects to award an Option
to an Employee, the number of Shares to be acquired on the exercise of such
Option shall be determined by the Board in its sole discretion, taking into
account the following criteria:

   a)  the annual salary of the Employee as at the Award Date in relation to the
       total annual salaries payable by the Issuer to all of its Employees as at
       the Award Date;
   b)  the length of time that the Employee has been employed by the Issuer; and
   c)  the quality of work performed by the Employee.

2.3  Notification of Award
     ---------------------

Following the approval by the Board of the awarding of an Option, the
Administrator shall notify the Option Holder in writing of the award and shall
enclose with such notice the Option Certificate representing the Option so
awarded.

2.4  Copy of Plan
     ------------

Each Option Holder, concurrently with the notice of the award of the Option,
shall be provided with a copy of the Plan.  A copy of any amendment to the shall
be promptly provided by the Administrator to each Option Holder.

2.5  Limitation
     ----------

The Plan does not give any Option Holder that is a Director the right to serve
or continue to serve as a Director of the Issuer nor does it give any Option
Holder that is an Employee the right to be or to continue to be employed by the
Issuer.

                                  ARTICLE III
                                  -----------
                        TERMS AND CONDITIONS OF OPTION
                        ------------------------------

3.1  Board to Allot Shares
     ---------------------

The shares to be issued to Option Holders upon the exercise of Options shall be
allotted and authorized for issuance by the Board prior to the exercise thereof.

                                       3
<PAGE>

3.2  Number of Shares
     ----------------

The Issuer shall not grant Options under the Plan which will, when exercised,
exceed 2,300,000 shares of Common Stock and shall not grant Options to any one
individual Director or Employee which will, when exercised, exceed five percent
(5%) of the issued and outstanding Shares of the Issuer.

If any Option expires or otherwise terminates for any reason without having been
exercised in full, the number of Shares in respect of which Option expired or
terminated shall again be available for the purposes of the Plan.

3.3  Term of Option
     --------------

Subject to paragraph 3.4, the Expiry Date of an Option shall be the date so
fixed by the Board, provided that such date shall not be later than the tenth
anniversary of the Award Date of such Option.

3.4  Termination of Option
     ---------------------

An Option Holder may exercise an Option in whole or in part at any time or from
time to time during the Exercise Period provided that, with respect to the
exercise of part of an Option, the Board may at any time and from time to time
fix a minimum or maximum number of Shares in respect of which an Option Holder
may exercise part of any Option held by such Option Holder.  Any Option or part
thereof not exercised within the Exercise Period shall terminate and become
null, void and of no effect as of 5:00 p.m. local time in Irving, Texas on the
Expiry Date.  The Expiry Date of an Option shall be the date so fixed by the
Board, subject to earlier termination as provided below.

a)   Death

     In the event that the Option Holder should die while he or she is still a
     Director (if he or she holds his or her Option as Director) or Employee (if
     he or she holds his or her Option as Employee), the Expiry Date shall be
     the first anniversary of the Option Holder's date of death; or

b)   Ceasing to hold Office

     In the event that the Option Holder holds his or her Option as Director of
     the Issuer and such Option Holder ceases to be a Director of the Issuer
     other than by reason of death, the Expiry Date of the Option shall be the
     30th day following the date the Option Holder ceases to be a Director of
     the Issuer as a result of:

          i.    ceasing to meet the qualifications under the laws of the State
                of Delaware; or
          ii.   a resolution having been passed by the shareholders of the
                Issuer or;
          iii.  by order of any regulatory body having jurisdiction to so order,


                                       4
<PAGE>

     in which case the Expiry Date shall be the date the Option Holder ceases to
     be a Director of the Issuer; or

c)   Ceasing to be Employed

     In the event that the Option Holder holds his or her Option as an Employee
     of the Issuer and such Option Holder ceases to be an Employee of the Issuer
     other than by reason of death or a Sale Transaction, the Expiry Date of the
     Option shall be the 30th day following the date the Option Holder ceases to
     be an Employee of the Issuer unless the Option Holder ceases to be an
     Employee of the Issuer as a result of:

          i.   termination for cause; or
          ii.  by the order of any regulatory body having jurisdiction to so
               order,

     in which case the Expiry Date shall be the date the Option Holder ceases to
     be an Employee of the Issuer.

d)   Sale Transaction

     In the event that the Option Holder holds his or her Option as an Employee
     of the Issuer and such Option Holder becomes an employee of the party (the
     "Acquiror") continuing or surviving any merger or acquiring a material
     portion of the assets of the Issuer in a Sale Transaction, the Expiry Date
     shall be the second anniversary of the date of consummation of the Sale
     Transaction.

e)   Alteration of Vesting and Exercise Periods

     Notwithstanding anything to the contrary contained in Section 3.4(a),
     3.4(b), 3.4(c) or 3.4(d), the Board may, in its discretion, designate
     shorter or longer periods to exercise Options following an Option Holder's
     termination of employment; provided, however, that any shorter periods
     determined by the Board shall be effective only if provided for in the
     instrument that evidences the grant to the Option Holder of such Option, or
     if such shorter period is agreed to in writing by the Option Holder.
     Notwithstanding anything to the contrary contained herein, Options shall be
     exercisable by an Option Holder following such Option Holder's termination
     of employment only to the extent that installments thereof have become
     exercisable on or prior to the date of such termination; provided that the
     Board may, in its discretion, elect to accelerate the vesting of all or any
     portion of any Options that have not vested on or prior to the date of such
     determination.

3.5  Exercise Price
     --------------

The price at which an Option Holder may purchase a Share upon the exercise of an
Option shall be the Market Value as of the Award Date.

                                       5
<PAGE>

3.6  Assignment of Options
     ---------------------

Options may not be assigned or transferred, provided however that the Personal
Representative of an Option Holder may, to the extent permitted by paragraph 4.
1, exercise the Option within the Exercise Period.

3.7  Adjustments
     -----------

If prior to the complete exercise of any Option the Shares are consolidated,
subdivided, converted, exchanged or reclassified or in any way substituted for
(collectively the "Event"), an Option, to the extent that it has not been
exercised, shall be adjusted by the Board in accordance with such Event in the
manner the Board deems appropriate.  No fractional Shares shall be issued upon
the exercise of the Options and accordingly, if as a result of the Event, an
Option Holder would become entitled to a fractional share, such Option Holder
shall have the right to purchase only the next lowest whole number of shares and
no payment or other adjustment will be made with respect to the fractional
interest so disregarded.

                                  ARTICLE IV
                                  ----------
                              EXERCISE OF OPTION
                              ------------------

4.1  Exercise of Option
     ------------------

a)   Exercise Price

     An Option may be exercised only by the Option Holder or the Personal
     Representative of any Option Holder.  An Option Holder or the Personal
     Representative of any Option Holder may exercise an Option in whole or in
     part at any time or from time to time during the Exercise Period up to 5:00
     p.m. local time in Irving, Texas on the Expiry Date by delivering to the
     Administrator an Exercise Notice, the applicable Option Certificate and
     either (a) a certified check or bank draft payable to Dial-Thru
     International Corporation, or (b) such other consideration as the Board may
     from time to time deem acceptable in a particular instance, in either case
     in an amount or having a fair market value (as determined by the Board)
     equal to the aggregate Exercise Price of the Shares to be purchased
     pursuant to the exercise of the Option.  In the discretion of this Board,
     payments for purchase or exercise of Options may be made by (i) matured
     capital stock of the Issuer (i.e., capital stock owned longer than six (6)
     months) delivered and transferred to the Issuer by or on behalf of the
     person exercising the Option and duly endorsed in blank or accompanied by
     stock powers duly endorsed in blank, with signatures guaranteed in
     accordance with the Securities Exchange Act of 1934, as amended, as
     required by the Board (valued at the Market Value as of the exercise date)
     or (ii) such other consideration as the Board may from time to time in the
     exercise of its discretion deem acceptable in any particular instance;
     provided, however, that the Board may, in the exercise of its discretion
     (i) allow the exercise of Options in a broker-assisted or similar
     transaction in which the exercise price is not received by the Issuer until
     promptly after exercise, and/or (ii) allow the Issuer to loan the
     applicable purchase or exercise price to the Option Holder, if the purchase
     or exercise will be followed by a prompt sale of some

                                       6
<PAGE>

     or all of the underlying shares and a portion of the sales proceeds is
     dedicated to full payment of the purchase or exercise price.

b)   Withholding Taxes

     Whenever the exercise of any Option granted under this Plan, or transfers
     of any shares issued upon the exercise of any Option, gives rise to tax or
     tax withholding liabilities or obligations, the Option Holder shall remit
     to the Issuer, in addition to the payment of the exercise price, an amount
     sufficient to satisfy any federal, state or local withholding tax
     requirements prior to the issuance of such shares. The Board may, in the
     exercise of its discretion, allow satisfaction of tax withholding
     requirements by accepting delivery of stock of the Company (or by
     withholding a portion of the stock otherwise issuable upon the exercise of
     an Option) or such other consideration as the Board may, in its discretion,
     deem acceptable.

4.2  Issues of Share Certificates
     ----------------------------

As soon as practicable following the receipt of the Exercise Notice, the
Administrator shall cause to be delivered to the Option Holder a certificate for
the Shares so purchased. If the number of Shares so purchased is less than the
number of Shares subject to the Option Certificate surrendered, the
Administrator shall forward a new Option Certificate to the Option Holder
concurrently with delivery of the aforesaid share certificate for the balance of
Shares available under the Option.

4.3  Condition of Issue
     ------------------

The issue of Shares by the Issuer pursuant to the exercise of an Option is
subject to this Plan and compliance with the laws, rules and regulations of all
regulatory bodies applicable to the issuance and distribution of such Shares and
to the listing requirements of any stock exchange or exchanges on which the
shares may be listed.  The Option Holder agrees to comply with all such laws,
rules and regulations and agrees to furnish to the Issuer any information,
report and/or undertakings required to comply with and to fully cooperate with
the Issuer in complying with such laws, rules and regulations.

                                   ARTICLE V
                                   ---------
                                ADMINISTRATION
                                --------------

5.1  Administration
     --------------

The Plan shall be administered by the Administrator on the instructions of the
Board.  The Board may make, amend and repeal at any time and from time to time
such regulations not inconsistent with the Plan as it may deem necessary or
advisable for the proper administration and operation of the Plan and such
regulations shall form part of the Plan.  The Board may delegate to the
Administrator or any Director, officer or employee of the Issuer such
administrative duties and powers as it may see fit.

                                       7
<PAGE>

5.2  Interpretation
     --------------

The interpretation by the Board of any of the provisions of the Plan and any
determination by it pursuant thereto shall be final and conclusive and shall not
be subject to any dispute by any Option Holder.  No member of the Board or any
person acting pursuant to authority delegated by it hereunder shall be liable
for any action or determination in connection with the Plan made or taken in
good faith and each member of the Board and each such person shall be entitled
to indemnification with respect to any such action or determination in the
manner provided for by the Issuer.

                                  ARTICLE VI
                                  ----------
                           AMENDMENT AND TERMINATION
                           -------------------------

6.1  Prospective Amendment
     ---------------------

The Board may from time to time amend the Plan and the terms and conditions of
any Option thereafter to be granted and, without limiting the generality of the
foregoing, may make such amendment for the purpose of meeting any changes in any
relevant law, rule or regulation applicable to the Plan, any Option or the
Shares, or for any other purpose which may be permitted by all relevant laws,
rules and regulations provided always that any such amendment shall not alter
the terms or conditions of any Option or impair any right of any Option Holder
pursuant to any Option awarded prior to such amendment.

6.2  Retrospective Amendment
     -----------------------

The Board may from time to time retrospectively amend the Plan and, with the
consent of the affected Option Holders, from time to time, retrospectively amend
the terms and conditions of any Options which have been theretofore granted,
including, without limitation, amendments to (a) accelerate or extend the
vesting or exercise period of any Option in whole or in part or (b) adjust or
reduce the exercise price of Options held by an Option Holder by cancellation of
such Options and granting of Options at a lower exercise price or by
modification, extension or renewal of any Options.

6.3  Termination
     -----------

The Board may terminate the Plan at any time provided that such termination
shall not alter the terms or conditions of any Option or impair any right of any
Option Holder pursuant to any Option awarded prior to the date of such
termination and notwithstanding such termination the Issuer, such Options and
such Option Holders shall continue to be governed by the provisions of the Plan.

                                       8
<PAGE>

6.4  Agreement
     ---------

The Issuer and every person to whom an Option is awarded hereunder shall be
bound by and subject to the terms and conditions of the Plan.  In case of any
conflict between the terms of the Plan or any Option, on the one hand, and any
employment agreement between an Option Holder and the Issuer (or any of its
subsidiaries), on the other hand, the terms and conditions of the employment
agreement shall apply with respect to those items specifically addressed in the
employment agreement.




                                       9
<PAGE>

                                         This document constitutes part of a
                                         prospectus covering securities that
                                         have been registered under the
                                         Securities Act of 1933.

                                 SCHEDULE "A"
                               Stock Option Plan
                               -----------------

TO:       The Administrator, Stock Option Plan
          c/o Dial-Thru International Corporation
          8100 Jetstar, Suite 100
          Irving, Texas  75063

The undersigned hereby irrevocably gives notice, pursuant to Dial-Thru
International Corporation (the "Company") Stock Option Plan (the "Plan"), of the
exercise of the Option to acquire and hereby subscribes for (cross out
inapplicable item):

     (a)  all of the Shares; or

     (b)  ______ of the Shares

which are the subject of the Option Certificate attached hereto.

The undersigned tenders herewith the sum of (a) either (i) a certified check or
bank draft payable to Dial-Thru International Corporation in an amount, (ii)
shares common stock of the Company that have been held for more than six (6)
months having an Market Value as of the date of exercise, or (iii) such other
consideration approved by the Board having an aggregate value (as determined by
the Board), in either such case equal to the aggregate Exercise Price of the
aforesaid shares plus (b) an amount sufficient to satisfy any federal, state or
local withholding tax requirements arising from the exercise of the Option,
payable by certified check or bank draft or, upon the approval by the Board of
Directors of the Company in its discretion, by delivery of shares of common
stock of the Company (or by withholding a portion of the stock otherwise
issuable in connection with the Option) or by the delivery of such other
consideration as the Board, in its discretion, may deem acceptable.  The
undersigned hereby directs the Company to issue the certificate evidencing said
shares in the name of the undersigned to be mailed to the undersigned at the
following address:

               ____________________________________________

               ____________________________________________

               ____________________________________________

DATED the ___________ day of ______________, 2000.


                                 ____________________________________________
                                 Signature of Option Holder

                                 ____________________________________________
                                 Name of Option Holder
                                 (Print)