Same happened here, as the post ( @Aleksandr ) stating selected payment plan, been waiting for money to come out, then other day get the letter stating two or so weeks to pay (by Oct 7) or it's going to start racking up interest and penalties!
Even worse, I compared the statement against my TurboTax return, and IRS has *already* attached some penaly fees! So, yet again, pandemic cripples country, and we the people are getting penalized for it due to impact delays???
Further bizarre; I tried to setup an online IRS account, to check what's going on. Turns out that I can't, but for the dumbest reason possible -- because I'm *overly* financially-responsible! To verify you're you, it wants either SS#/Tax ID & one of the following: credit card (none of my bank debit cards work, and has a note saying that most debits won't), car loan policy#, student loan policy#, home-finance policy# (oddly no option for driver's license, etc). I'm middle-aged and went to great lengths to pay off all loans/debt, so debt wouldn't follow and cripple me later on into retirement. But now, I can't easily reference IRS, to attempt GIVING THEM money, all because I have no debt. Perhaps whoever thought up the logistics of how that setup works --perhaps they should be getting the penalties with interest!
-_-
