The Truth in Lending Act requires that:
The due date must be the same day each month. The due date could be set as the last day of the month or it could be a specific date in the month, such as the 4th.
If the payment due date falls on a weekend or a federal holiday when the bank does not accept or receive mailed payments, then any mailed payment received by the bank before the cut-off time on the next business day would be considered an on-time payment.
The payment cut-off time cannot be earlier than 5:00 p.m. on the due date.
If you mail a payment and the due date falls on a federal holiday, then the bank must receive your payment before the cut-off time on the next business day after the federal holiday for your payment to be on time. However, if the bank accepts or receives payments on the due date by a method other than mail—such as electronic or telephone payments—and you make a payment using one of these alternative methods, you would still need to make the payment by the cut-off time on the due date.
If you believe you were incorrectly charged a late payment fee, you can dispute the charge with the bank. Notify your bank in writing using the billing error notice instructions, which should be on the back of your monthly billing statement. Be sure to use the address specified after Send Billing Inquiries to: or similar on the back of the billing statement. This is usually not the same address where you send your payment.
Refer to 12 CFR 1026 Truth in Lending (Regulation Z) for more information.