New client received a letter stating that an amended tax return was filed for the 2019 C corporation 1120 return. An amended return was never filed. The original 2019 1120 return, which was the first corporate return which I prepared for this new client, was mailed by client in June of 2020.... The IRS letter States "Our records show we received your amended tax return for the tax period listed above. We're sorry but we can't find it, so we need your help to finish processing your tax return. It is possible that our records show the receipt of an amended/corrected Form 1120-S in error. If you filed an amended/corrected return, please send a complete, newly signed copy. If you did not file an amended/corrected return, please advise us so we can correct your account."    You will notice that they referenced 1120-S but it is a regular C Corp, which they state at the top of the letter letter (they state Form: 1120).  They do have a fax number where a response can be faxed to them....