Did you ever get this resolved? I have the same situation. Switched from MFS to MFJ for 2021 and they took the amount from line 11 and said it was additional tax assessed even though that is what my wife had already paid. I was supposed to get $4222 refunded and now they say I owe them $1483. It is ridiculous. I cant even get any of these clowns from the IRS on the phone. I am stuck at this point. To top it off, they NEVER notified me of any errors on my amendment. I filed it in February 2024 and didn't receive a thing until June 2025.
