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.The Illinois Department of Revenue (IDOR) sends letters and notices to request additional information and support for information you report on your tax return. Why is my refund taking so long? Refund time frames can vary. Sending an IRS audit reconsideration request? Please visit us at IRS. Please visit us at IRS. I confirm that I am the taxpayer listed above. Sign up for Tax Refund Alerts. Email.