tl;dr: the IRS made a mistake regarding my 2016 tax return, and after a year of phone calls and letters back and forth they can't seem to fix it. Is there a good chance I'll have any better luck by going to the local IRS office in person?
Details: I filed my 2016 return in April 2017. Later I realized we missed one of my wife's W2 forms so we amended the return in Oct 2017 and sent in the additional tax payment of approx $2500. The check cleared in Nov 2017, and in Dec 2017 we received a letter saying we owed interest on the additional tax since it was 6 months late. The interest came out to about $50, we paid it, and that payment cleared in Dec 2017. Life was good.
A few months later in 2018 we received a CP2000 letter from the IRS saying we missed a W2 on our tax return and we owed $2500! At first it seemed like a simple mistake: maybe this letter had been triggered before the amended was received, and somehow got accidentally sent out months later. But upon further inspection, the starting numbers the form used for the income calculation were the amended numbers, not those from the original return. In other words the CP2000 was trying to add in the same missed W2 that we already added in to the amended. I have sent multiple letters explaining this, and multiple phone calls, and the IRS still thinks we owe them $2500 + interest. Two weeks ago we received a letter which made me believe the problem was nearly resolved; the letter stated we had paid the $2500, and now only owe about $240 more in interest. Of course that's wrong since we already paid the interest in 2017, but this was the first time they at least admitted the $2500 was already paid. I hadn't bothered to call yet about that letter, but today I got another letter stating I owe $2500 again, plus about $200 in interest, as if the letter from two weeks ago didn't exist. Life is annoying.
Since the snafu still persists, I'm now wondering if I might have better luck bringing all my documentation to an IRS office and seeing if I can get them to fix this once and for all. But I don't want to take a half day off of work just to end up banging my head against the wall in front of an IRS employee. Or worse yet, I don't want the IRS employee to tell me they get it, and yeah it's an obvious mistake, but there's nothing they can do about it there; I have to send in a letter...