We have identified the following overpayment and are in good faith voluntarily refunding all monies collected in error. Once the Cost Containment Unit (CCU) has reviewed the overpayment, you will receive a letter explaining the details of the reconciliation.In this article, we discuss how to write a refund request letter, what to include in the letter, and provide a sample refund request letter. Please download the form, complete each field and print. Include the form with your refund so we can properly apply the refund and record the receipt. Report an overpayment. Complete an overpayment refund form to notify First Coast of an overpayment prior to receiving a demand letter. When you identify a Medicare overpayment, use the Overpayment Refund Formto submit the voluntary refund. To request a tax refund, file an Application for Refund - Sales and Use Tax (Form DR-26S) or Application for Refund - All Other Taxes (Form DR-26). If we have identified an overpayment and request a refund, please mail the check along with a copy of the overpayment request letter we sent you.