You are lucky. We got the same thing, but I got the notice in October. I called and sent the info showing our return was timely filed, they put a hold on the account so no further process for 9 weeks. I called 9 weeks later and they said they had only gotten to September correspondence. Another 9 week hold. I have not been able to connect since. Smart thing to do is to file an extension request, and then file whenever, timely or otherwise (as long as you file before the end of the extension period!).
I had proof it was mailed in time. I called the number listed on the letter they sent. After two hours on hold I spoke with a rep who said we were ok. Then I got a letter confirming that we were not late and there were no penalties.
Since 2021 Summer. Every time I receive a letter from the IRS to pay, I reply with the receipt and "nothing" happens. The last letter they threaten with a Lien on my assets. At this this point I paid the penalty (a month ago)
If you sent the IRS anything by USPS, they are many months behind in dealing with the mail. Wen did you send the first respsonse, and what communications have you recevied from the IRS (of any type) since then? My professional experience suggests that you probably received addtional penalty/interest due notices since the IRS had not yet processed your response. At some point, they will, and all penalties/interest should be reversed.
Like I said before, Even Though we filed by March 10th - The USPS received it March 30th - We got penalized for late filing. This made me furious. I've sent them multiple letters with copies of certified mail receipt
After USPS mailing the 7004 by certified mail with request
for a return receipt I tried to see if TurboTax (Windows)
would e-file a request for an extension on my personal
return. TurboTax would NOT efile but would print the form
(Form 4868). The Intuit website at:
(https://turbotax.intuit.com/irs-tax-extensions/) indicates
that "Free federal tax extension available in March".
Last year's experience with USPS Certified Mail & Return
receipt was not satisfactory. I never received the return
receipt card. A CPA I work with related that USPS -
Certified Mail with a return receipt is no longer proof of
transmittal US Tax Court (https://www.ustaxcourt.gov/)