I request that you send a replacement refund, and if I receive two refunds, I will return one. Use Form 843 to claim a refund or request an abatement of certain taxes, interest, penalties, fees, and additions to tax.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. Members should fill out and submit Form 5 (Withdrawing Your Retirement Service Credit and Contributions) to the Retirement Systems Division. The Department will send a garnishment release letter to the taxpayer's employer once the tax liability is paid in full. Use Form 843 to claim a refund or request an abatement of certain taxes, penalties, additions to tax, interest, and fees. The primary letter we use to request information about a return is Form DTF948 or DTF948O, Request for Information (RFI). The Illinois Department of Revenue (IDOR) sends letters and notices to request additional information and support for information you report on your tax return.