Note: You must complete a separate Form 3911 for each refund for which you are requesting information. 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. I am the defendant for this cause number. A taxpayer must apply for a refund within three years of making the payment. Use Form 843 to claim a refund or request an abatement of certain taxes, penalties, additions to tax, interest, and fees. Completing an online form and writing a signature on a computer. Learn How to Request Benefit Payments.