(1) As used in this section, "credit card guaranty" means an agreement pursuant to which a natural person assumes liability for indebtedness to a credit union incurred by use of a credit card without receiving the contractual right to obtain extensions of credit under the account for which the credit card is issued.
(2) No credit card guaranty shall be valid or enforceable unless it is in writing signed by the guarantor and contains a provision specifying the amount of the maximum aggregate liability of the guarantor thereunder.