This brief but important letter notifies a customer that he or she has overpaid you. It can serve as a very good customer relations letter.Our document template is designed to make the process of writing an "Inform a Customer of an Overpayment" letter quick, easy, and stress-free. You have to tell your credit or debit card company about any error you're disputing within 60 days of when the first statement with the charge was sent to you. How do you write a letter to inform of a double payment? We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. Discover how our refund letter to customer template can enhance satisfaction and loyalty, with professional tips for seamless communication.