Prompt Credit for Payment. An issuer must credit your account the day payment is received. The exceptions are if the payment is not made according to the creditor's requirements, or the delay in crediting your account won't result in a charge.
To help avoid finance charges, follow the issuer's mailing instructions. Payments sent to the wrong address could delay crediting your account for up to five days. If you misplace your payment envelope, look for the payment address on your billing statement or call the issuer.
Refunds of Credit Balances. When you make a return or pay more than the total balance at present, you can keep the credit on your account or write your issuer for a refund - if it's more than a dollar. A refund must be issued within seven business days of receiving your request. If a credit stays on your account for more than six months, the issuer must make a good faith effort to send you a refund.
Errors on Your Bill. Issuers must follow rules for promptly correcting billing errors. You'll get a statement outlining these rules when you open an account and at least once a year. In fact, many issuers include a summary of these rights on your bills.
If you find a mistake on your bill, you can dispute the charge and withhold payment on that amount while the charge is being investigated. The error might be a charge for the wrong amount, for something you didn't accept, or for an item that wasn't delivered as agreed. Of course, you still have to pay any part of the bill that's not in dispute, including finance and other charges.

