Are they backlogged on sending bills and notices as well?
I went to the IRS website on some unrelated business, and while I was there I noticed that I had an amount due from 2018. No explanation, and I never received any notice in the mail. I called them to see what it was for, and they could only say that their computers were down.
I was advised to pay the amount to stop interest from accumulating, and then sort it out later. But I'm not sure when "later" is, or at what point I need to start inquiring further.