Citizen to IRS.
I filed that return. What, you’ve never heard of lost mail before? You’ve never heard of the government misplacing or losing anything before?
That would never fly, and neither should their bogus response.
Don’t send a check and don’t file a return. When the IRS asks you about it tell them you did and they must have lost it in a computer crash. Everyone now knows that they have no backup systems at all. lol