What this notice is about You did not respond to a previous request for missing or incomplete information on your return and your return is late. What you need to do Send the incomplete/missing information described in the “About your return” section on the notice. Include the contact voucher at the end of the notice. Send the amount due to avoid interest charges. You may want to If the reason your return was incomplete was beyond your control, send us a signed explanation with any supporting documentation. Frequently asked questions Q. What if I disagree with the penalty? A. Send a written statement with any supporting documentation to the address on the notice. Reference Tools Publication 5027, Identity Theft Information for Taxpayers PDF Full list of tax forms and instructions Need Help? You can authorize someone to contact the IRS on your behalf. See if you qualify for help from a Low Income Taxpayer Clinic. If you can’t find what you need online, call the IRS number at the top of your notice or letter.