I.R.S. attempts to spread fear !

Yesterday, after posting on this forum. I went to my mail box to see what surprises I might find there.
The mother of all surprises the I.R.S. had a letter for little ol` me. I must be important to them.
As I posted here earlier : I went to the I.R.S. to see about Mike Castro`s tax situation. What was said and done will remain no one`s business. Suffice it to say I left there smarter. This all occured last Thursday and Friday.
Now on Monday I have this letter from the I.R.S. Inside it says they have failed to recieve a tax form from me for the year of such and such.
Disclaimer: I always enjoy the challenge of doing my taxes. Have always filed all nessasarry forms as requested.
So I went to my files to check my records on year such and such. Yep in year such and such I did this form and sent it in. Now they are saying THEY DID NOT RECIEVE IT. Well no law broken right? I did my part, right? Right away I called my book keeper. She said "no problem make a copy of the form and send it in w/ the form to be filed as they requisted."
The form they are requesting me to send in ask (as if it were true) "why should I not be required to pay taxes for year such + such." As if I were a criminal. As if I were dumb enough to implicate my self. It starts innocent enough, it ask: if you are blind, if you are over 65, if you are recently widowed, if you are married and filing jointly. They know the answers to these questions from the other forms filed 4 that year. None of which pertain to me. So the only thing I needed to answer on their form was my full name and S.S. #. Which was already on the top of this form.
Then under penalty of perjury, I sign this form.
I am not really afraid, more like concerned.
How does going to the I.R.S. and asking question about Mike Castro. Cause them to lose forms on me suddenly?
Is this another flea from Casto that I must now have to deal with? scratch scratch
Mike Casro must certainly be a confidential informent.
Good thing I kept all these records.
You all can bet, I have only just began to fight.