If it were me, I'd be all over that CPA like a cheap suit until they took responsibility for and resolved this. Isn't this what you pay them for?
Maybe it's a bit too soon, but have you tried contacting your senator/congressman? I had an issue with the treasury dept. a few years back and filled out a form on my senator's website. One of her staffers contacted the agency on my behalf and the issue got resolved in relatively short order. Couldn't hurt...it's part of their job.
Glad my finances aren't so complex I need anything more than Turbotax/HR Block software to file.
My finances only became complicated due to the 1.4% interest I owned in a local California business park.
I had sold a rental home that had been my home years ago and put the proceeds into a private Real Estate Investment Trust that built out a small business park... very simple transaction via 1031 exchange and I was pleased with my good fortune.
About 7 years ago the major wealthy investors of the Business Park saw the handwriting on the wall and elected to sell the California business park and use the proceeds to purchase investment property in a dozen states...
So my little home of many years ago that had become a small interest in the local business park was now a miniscule interest in a dozen properties spread over a dozen states...
The complexity is because most of these states have state income tax requiring me to file returns in states I have never visited... i. e. the $65 I owed in Arizona or $150 in Oklahoma, etc.
Don't get me wrong... for a nobody like myself with a day job taking the proceeds from one little East Oakland house back in the 90's into hotels, storage units, R and D property, etc... is beyond imagination... plus no one is calling me at midnight saying a pipe bursts or a toilet is plugged!
I do think my CPA is struggling filing in multiple states... I am the only client in the firm filing in Oklahoma as and example.
The $1200 in professional CPA fees I have been paying isn't enough for a nationwide firm to even speak with me.
The end game is possibly taking the private REIT public so ownership would be shares of stock as opposed to percentage of individual property... which would great simplify my tax life.
For a simple guy like myself there is no way I have the knowledge to file in multiple states and my CPA firm is also finding it challenging because other state filings impact California filing...
Not sure if my explanation makes sense but it's how I got to where I am...