Section 19. (a) The creditor shall mail or deliver to the customer the statement or statements required by subsection (b) of section eleven for each billing cycle at least 14 days before the end of the next succeeding billing cycle or the payment due date, whichever is earlier. If the creditor fails to mail or deliver such statement or statements within the specified period, he shall not be entitled to any finance charge with respect to the next succeeding billing cycle based upon the balance of the preceding billing cycle.

If any such finance charge is assessed or collected, the customer shall receive a credit or refund for any such finance charge assessed or collected other than in accordance with the provisions of this section within the two billing cycles following such assessment or collection, the failure to provide such credit or refund within the period specified shall subject the creditor to the penalties provided in section thirty-two.

(b) Subsection (a) shall not apply in any case where a creditor has been prevented, delayed or hindered in making timely mailing or delivery of such periodic statement within the time period specified in said subsection because of an act of God, war, natural disaster, strike or other excusable or justifiable cause, as determined by the commissioner.