Any amendment of a revolving credit plan which violates the conditions or limitations of Section 8 of this Act shall not be enforceable, but such plan shall remain enforceable according to its original terms. Any borrower whose revolving credit plan has been unlawfully amended may recover by means of an action or defense an amount equal to twice the amount by which such borrower’s payments of interest and charges were increased solely due to such unlawful amendment, plus such reasonable attorneys’ fees and court costs as may be assessed by a court against the financial institution. Recovery by means of a defense may be had at any time after such amendment purports to be effective. Recovery by means of an action may be had at any time after such amendment purports to be effective and prior to the expiration of 2 years after the earlier of (1) the date the last payment of such unlawfully increased interest or charges, or (2) the date on which the borrower’s plan has been terminated. A bona fide error in connection with the amendment of a revolving credit plan shall not be a violation under this Section if the financial institution corrects the error within a reasonable time.