(a) If a receiving bank accepts a payment order issued in the name of its customer as sender which is:
(i) Not authorized and not effective as the order of the customer under § 47-4A-202; or
(ii) Not enforceable, in whole or in part, against the customer under § 47-4A-203;
(b) Reasonable time under subsection (a) may be fixed by agreement as stated in § 47-1-302(b), but the obligation of a receiving bank to refund payment as stated in subsection (a) may not otherwise be varied by agreement.