To apply for a tax refund, the taxpayer or representative must complete Sections 1 through 5 of this application. Over Payment Refund Letter To Customers Template.Did the IRS change your tax return check amount? Here's everything you need to know about responding to an adjusted refund letter. Clearly state the decision regarding the refund. Submit a letter requesting a refund and the Refund Form (pdf) to receive a refund for overpayments made to the PACER Service Center. ☐ The Refund reason(s) is not vague such as "Overpayment", "Filing error", "Amended my Return", or "Credit on my Account". First, you need to issue a check to your customer using the Accounts Receivable account for the overpayment amount.