An overpayment claimed on a return may be applied as a credit for your next year's estimated tax or you may request that it be refunded to you. How Should I Respond?When you identify a Medicare overpayment, use the Overpayment Refund Formto submit the voluntary refund. Check the box below that indicates your reason for filing Form 843. Tax. Abatement or refund of tax other than income, estate, or gift tax. INSTRUCTIONS: Please complete, sign and submit this form to request a Federal tax refund from the. Office of the Comptroller. If the DUA says that you were overpaid, you can challenge their decision. You can also challenge the amount of the overpayment. Overpayments will be applied to the next quarter unless it is the last quarter of the fiscal year.