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                                                                   Exhibit 10.70

                              THIRD AMENDMENT TO
                             AMENDED AND RESTATED
                          REVOLVING CREDIT AGREEMENT


     Third Amendment dated as of March 31, 2000 to Amended and Restated
Revolving Credit Agreement (the "Third Amendment"), by and among TIER
TECHNOLOGIES, INC., a California corporation (the "Company"), TIER TECHNOLOGIES
(UNITED KINGDOM), INC., a Delaware corporation ("Tier UK" and, collectively with
the Company, the "Borrowers" and each individually, a "Borrower") and FLEET
NATIONAL BANK (formerly known as BankBoston, N.A.) (the "Bank"), amending
certain provisions of the Amended and Restated Revolving Credit Agreement dated
as of May 28, 1999 (as amended and in effect from time to time, the "Credit
Agreement") by and among the Borrowers and the Bank. Terms not otherwise defined
herein which are defined in the Credit Agreement shall have the same respective
meanings herein as therein.

     WHEREAS, the Borrowers and the Bank have agreed to modify certain terms and
conditions of the Credit Agreement as specifically set forth in this Third
Amendment;

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
contained herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

     (S)1.  Amendment to (S)1 of the Credit Agreement. Section 1.1 of the Credit
            -----------------------------------------
Agreement is hereby amended as follows:

     (a)    the definition of "Loan Documents" is hereby amended by inserting
immediately after the words "Collateral Instrument" a comma and the words "the
Subordination Agreement";

     (b)    Section 1.1 is further amended by inserting the following
definitions in the appropriate alphabetical order:

                 Chapman Acquisition. The acquisition by the Company of certain
                 -------------------
     of the assets of Harris Chapman pursuant to the terms of the Chapman
     Purchase Agreement for an aggregate purchase price of not more than
     $2,049,000.

                 Chapman Purchase Agreements.  That certain Agreement for
                 ---------------------------
     Purchase and Sale of Assets dated as of March 9, 2000 by and among Harris
     Chapman, a Florida corporation, Richard E. Kristensen and the Company.

                 Purchase Agreements.  Collectively, the SCA Purchase Agreement
                 -------------------
     and the Chapman Purchase Agreement.
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                                      -2-


          SCA Acquisition.  The acquisition by the Company of certain of the
          ---------------
     assets of The SCA Group, Inc. pursuant to the terms of the SCA Purchase
     Agreement for an aggregate purchase price of not more than $14,455,000.

          SCA Purchase Agreement.  That certain Agreement for Purchase and Sale
          ----------------------
     of Assets dated as of March 9, 2000 by and among The SCA Group, Inc.,
     George R. Stout and the Company.

          SCA Security Agreement.  That certain Security Agreement dated as of
          ----------------------
     March 31, 2000 by and between The SCA Group, Inc. and the Company, which
     agreement shall be in form and substance satisfactory to the Bank.

          Subordination Agreement.  That certain Intercreditor Agreement dated
          -----------------------
     as of the date hereof by and among The SCA Group, Inc., the Bank and the
     Company, which agreement shall be in form and substance satisfactory to the
     Bank.

     (S)2.  Amendment to (S)5 of the Credit Agreement.  Section 5 of the Credit
            -----------------------------------------
Agreement is hereby amended as follows:

     (a)    Section 5.8 of the Credit Agreement is hereby amended by deleting
the amount "$3,700,000" which appears in subparagraph (d) of Section 5.8 and
substituting in place thereof the amount "$2,300,000".

     (b)    Section 5.9 of the Credit Agreement is hereby amended by deleting
the ratio "(less than)1.75" which appears in the table set forth in Section 5.9
and substituting in place thereof the ratio "(less than)4.70".

     (S)3.  Amendment to Section 6 of the Credit Agreement.  Section 6 of the
            ----------------------------------------------
Credit Agreement is hereby amended as follows:

     (a)    Section 6.1(f) of the Credit Agreement is hereby amended by deleting
the words "Indebtedness does not exceed $5,000,000 outstanding at any time"
which appear in Section 6.1(f) and substituting in place thereof the words
"Indebtedness does not exceed (i) $5,000,000 outstanding at any time from the
Closing Date through December 30, 1999; and (ii) $8,000,000 outstanding at any
time thereafter".

     (b)    Section 6.1(j) of the Credit Agreement is hereby amended by deleting
the word "and" which appears at the end of Section 6.1(j).

     (c)    Section 6.1(k) of the Credit Agreement is hereby amended by deleting
the period which appears at the end of Section 6.1(k) and substituting in place
thereof a semicolon and the word "and".

     (d)    Section 6.1 of the Credit Agreement is amended by inserting
immediately after the text of Section 6.1(k) the following:
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                                      -3-

     (k)    Indebtedness of the Company to (i) The SCA Group, Inc. in an
aggregate principal amount of not more than $14,455,000 pursuant to the terms of
the SCA Purchase Agreement provided that the Borrower reduces the amount of such
                           --------
Indebtedness to an aggregate amount of not more than $9,850,000 by not later
than April 10, 2000 and (ii) Harris Chapman in an aggregate principal amount of
not more than $2,049,000 pursuant to the terms of the Chapman Purchase Agreement
provided that the Borrower reduces the amount of such Indebtedness to an
--------
aggregate amount of not more than $1,549,000 by not later than April 10, 2000.

     (e)    Section 6.3 of the Credit Agreement is amended by deleting the
amount "$1,000,000" which appears in Section 6.3 of the Credit Agreement and
substituting in place thereof the amount "$1,700,000".

     (f)    Section 6.5 of the Credit Agreement is hereby amended by (i)
deleting the word "and" which appears at the end of Section 6.5(f); (ii)
deleting the period which appears at the end of Section 6.5(g) and substituting
in place thereof a semicolon and the word "and"; and (iii) inserting immediately
at the end of Section 6.5(g) the following:

     (h)    liens in favor of The SCA Group, Inc. on certain of the assets of
the Company pursuant to the SCA Security Agreement to secure not more than
$4,950,000 of the Indebtedness permitted by Section 6.1(l), and solely to secure
that portion of the Indebtedness incurred solely pursuant to Section 2.4(b) of
the SCA Purchase Agreement.

     (g)    Section 6.6 of the Credit Agreement is hereby amended by deleting
Section 6.6 in its entirety and restating it as follows:

            6.6.  Merger; Consolidation; Sale or Lease of Assets; Other
                  -----------------------------------------------------
Acquisitions. Neither the Company nor any of its Subsidiaries shall sell, lease
------------
     or otherwise dispose of assets or properties in excess of $100,000 during
     any fiscal year (valued at the lower of cost or market), other than sales
     of inventory in the ordinary course of business in any fiscal year; or
     liquidate, merge or consolidate into or with any other person or entity, or
     otherwise acquire any other entity, provided that any Subsidiary of the
     Company may merge or consolidate into or with (i) the Company if no Default
     would result from such merger and if the Company is the surviving company,
     or (ii) any other wholly-owned Subsidiary of the Company and provided
                                                                  --------
     further, that the Company or any Subsidiary of the Company may enter into
     -------
     the SCA Acquisition, the Chapman Acquisition or a merger or acquire any
     other entity or other assets so long as, in each case, (a) in the case of a
     merger, the Company or such Subsidiary, as the case may be, is the
     surviving entity of such merger; (b) no Default or Event of Default has
     occurred and is continuing or would exist as a result of the merger or
     acquisition, as the case may be; (c) the Company has delivered to the Bank
     seven (7) Business Day's prior written notice of such merger or
     acquisition, which notice shall provide the Bank with a reasonably detailed
     description of the proposed merger or
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                                      -4-

     acquisition; (d) the business to be acquired would not subject the Bank to
     regulatory or third party approvals in connection with the exercise of any
     of their rights and remedies under this Agreement or the other Loan
     Documents; (e) the business or assets so acquired shall be acquired free
     and clear of all liens, encumbrances and Indebtedness, provided, however,
     as to the SCA Acquisition, the sellers shall be entitled to a security
     interest in certain of the assets of the Company pursuant to the terms of
     the SCA Security Agreement so long as such security interest is
     subordinated to the security interest in favor of the Bank pursuant to the
     terms of the Subordination Agreement; (f) the Company or such other
     applicable Person involved in the acquisition or merger has taken or caused
     to be taken all necessary action to grant to the Bank a first priority
     perfected lien in all assets and capital stock or other equity interests to
     be acquired in connection with such acquisition or merger (including,
     without limitation, the SCA Acquisition and the Chapman Acquisition), to
     the extent provided in the applicable provisions of Section VIII; (g) any
     new Domestic Subsidiary formed as a result of such acquisition or merger
     shall become a Guarantor hereunder and shall execute and deliver to the
     Bank all applicable Security Documents; (h) the Company has demonstrated to
     the satisfaction of the Bank, based on a pro forma compliance certificate,
                                              ---------
     compliance with all the financial covenants contained herein on a pro forma
     basis immediately prior to and after giving effect to such acquisition or
     merger (provided, to the extent the Company is not able to calculate such
     pro forma compliance due to the accounting methods used by the Person to be
     acquired or merged, the Company shall deliver to the Bank a certification
     that, to the best of the Company's knowledge, no Default or Event of
     Default will exist after giving effect to the acquisition and, in addition,
     the Company shall be required to deliver such pro forma compliance
     certificate within sixty (60) days from the date of the consummation of the
     acquisition or merger); and (i) the aggregate purchase price consisting of
     any consideration other than the capital stock of the Company for any
     single acquisition or merger or series of related acquisitions or mergers
     shall not exceed $14,455,000 in the case of the SCA Acquisition, $2,049,000
     in the case of the Chapman Acquisition and $5,000,000 in all other cases
     and the aggregate purchase price consisting of any consideration other than
     the capital stock of the Company for all mergers and acquisitions shall not
     exceed $18,700,000 over the life of this Agreement.

     (S)4.  Conditions to Effectiveness.  This Third Amendment shall not become
            ---------------------------
effective until the Bank receives the following:

     (a)    a counterpart of this Third Amendment, executed by the Borrowers and
the Banks;

     (b)    a counterpart of the Subordination Agreement, executed by the
Company, the Bank and The SCA Group, Inc.;
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                                      -5-

     (c)    executed copies of each of the SCA Purchase Agreement, the Chapman
Purchase Agreement and the SCA Security Agreement (together with any other
documents or instruments executed in connection therewith);

     (d)    evidence satisfactory to the Bank that all of the conditions set
forth in Section 6.6 of the Credit Agreement have been satisfied; and

     (e)    payment to the Bank of an amendment fee in the amount of $8,000 for
the account of the Bank.

     (S)5.  Representations and Warranties.  The Borrowers hereby repeat, on
            ------------------------------
and as of the date hereof, each of the representations and warranties made by
them in (S)4 of the Credit Agreement, and such representations and warranties
remain true as of the date hereof (except to the extent of changes resulting
from transactions contemplated or permitted by the Credit Agreement and the
other Loan Documents and changes occurring in the ordinary course of business
that singly or in the aggregate are not materially adverse, and to the extent
that such representations and warranties relate expressly to an earlier date),
provided, that all references therein to the Credit Agreement shall refer to
--------
such Credit Agreement as amended hereby.  In addition, each Borrower hereby
represents and warrants that the execution and delivery by each Borrower and its
Subsidiaries of this Third Amendment and the performance by such Borrower and
its Subsidiaries of all of its agreements and obligations under the Credit
Agreement as amended hereby and the other Loan Documents are within the
corporate authority of each such Borrower and its Subsidiaries and has been duly
authorized by all necessary corporate action on the part of such Borrower and
its Subsidiaries.

     (S)6.  Ratification, Etc.  Except as expressly amended hereby, the Credit
            ------------  ---
Agreement, the Security Documents and all documents, instruments and agreements
related thereto are hereby ratified and confirmed in all respects and shall
continue in full force and effect.  The Credit Agreement and this Third
Amendment shall be read and construed as a single agreement.  All references in
the Credit Agreement or any related agreement or instrument to the Credit
Agreement shall hereafter refer to the Credit Agreement as amended hereby.

     (S)7.  No Waiver.  Nothing contained herein shall constitute a waiver of,
            ---------
impair or otherwise affect any Obligations, any other obligation of the
Borrowers or any rights of the Bank consequent thereon.

     (S)8.  Counterparts.  This Third Amendment may be executed in one or more
            ------------
counterparts, each of which shall be deemed an original but which together shall
constitute one and the same instrument.

     (S)9.  Governing Law.  THIS THIRD AMENDMENT SHALL BE GOVERNED BY, AND
            -------------
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS
(WITHOUT REFERENCE TO CONFLICT OF LAWS).
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                                      -6-

     IN WITNESS WHEREOF, the parties hereto have executed this Third Amendment
as a document under seal as of the date first above written.

                              TIER TECHNOLOGIES, INC.


                              By:/s/ Laura B. DePole
                                 ---------------------------------
                              Title:  Chief Financial Officer

                              TIER TECHNOLOGIES
                                (UNITED KINGDOM), INC.


                              By: /s/ James L. Bildner
                                 ---------------------------------
                              Title: Director

                              FLEET NATIONAL BANK


                              By: /s/ illegible
                                 ---------------------------------
                              Title:  S.V.P.