425.103 Accrual of cause of action; “default.”
(1) Notwithstanding any term or agreement to the contrary, no cause of action with respect to the obligation of a customer in a consumer credit transaction shall accrue in favor of a creditor except by reason of a default, as defined in sub. (2).
(2) “Default”, with respect to a consumer credit transaction, means without justification under any law:
. . . .
(b) With respect to an open−end plan, failure to pay when due on 2 occasions within any 12−month period;
. . . .