I had the exact same problem for my 2017 taxes and didn't find out until just the other day.
I got a letter from the IRS saying I had a credit on my account from my 2017 taxes so I called them and they said that they just needed me to resend my tax return along with a copy of notice and they will then contact me to apply the credit to another year if I chose. I logged into my turbo tax and never saw anything about them being rejected and printed out my docs and mailed them in sometime in September 2020. The all of a sudden, I logged in to pay for my 2020 taxes and I am being charged late fees and on this itemized account form it states that I filed my taxes IN September of 2020 for 2017. I am so upset and confused. I searched all my emails and the last email I got from Turbo tax for that year was that my returns were pending and when we logged in to make the payment on the IRS website in 2018 for 2017 - it showed that we owed the amount that turbotax showed so we had assumed that our taxes were sent and accepted. I logged into my turbo tax and out of the blue it says "rejected" for fed and state (but my state AZ paid us our refund and they haven't sent us anything stating we never filed.) I don't know where to begin or what to do.
