Product: Checking or savings account

I sent a check for {$5900.00} made out to the US Treasury along with my tax return via the US Mail to the IRS on XX/XX/XXXX. The envelope was postmarked but was opened in transit and my check was removed from the envelope and cashed by someone at a XXXX XXXX ATM. XXXX XXXX should not have allowed the check to be cashed/deposited when clearly the check was made out to the US Treasury and the Treasury does not deposit checks in a XXXX XXXXXXXX  ATM . On XX/XX/XXXX, I learned that my check was intercepted and cashed by someone other than the US Treasury, I contacted my bank ( Citizens Bank ) immediately and opened a fraud case. Citizens Bank asked me to submit some paperwork, which I completed and submitted to Citizens Bank on XX/XX/XXXXXX/XX/XXXX. Since that time Citizens Bank has not been able to move the fraud case forward with XXXX XXXX. XXXX XXXX has apparently not been responsive and Citizens has not refunded my money back. I have asked for a provisional refund of my money because clearly this was a mistake by XXXX XXXX but Citizens has not complied. I am still waiting to receive my {$5900.00} money back from Citizens Bank. My complaint is with Citizens Bank although the root of the problem is that XXXX XXXX shouldn't have cashed the check and should be responsive to Citizens Bank. But I would prefer to be out of their business. They are holding my money XXXX while the investigate a case that is clearly a case of fraud. I have communicated with them on multiple dates but they have been not responsive. These dates include : - XXXX - called Citizens Bank. They said they are working on it and that XXXX XXXX said they would get back to them after XX/XX/XXXX, but they hadn't. The Citizens Bank person told me she would email the supervisor and call today. They said they would then call me back with an update. They never called me back. 
- XX/XX/XXXX - called Citizens Bank. They said they were going to follow up on XX/XX/XXXX. They said they would call me back by XX/XX/XXXX. They never did call me back. They said XXXX XXXX needs to process the refund. She suggested I call XXXX XXXX to see what's going on because XXXX XXXX has been non responsive. 
- XX/XX/XXXX - called XXXX XXXX. She was surprised that Citizens Bank said to call them. She said she couldn't give me any information or talk about the investigation and why it's not moving forward because they only deal with the banks. She said I should ask Citizens Bank for a provisional credit. 
- XXXX - I called Citizens Bank and they said they had not heard from XXXX XXXX. They said they will call today. They call every two weeks. She said to go to the branch office and request a provisional refund. 
- XXXX - I visited the local branch of Citizens Bank to request a provisional refund. He called his supervisor and requested the refund while I was there. 
- XXXX - I called the contact at the Citizens Bank to check on the provisional refund. He said that Citizens Bank called XXXX XXXX on XX/XX/XXXX and there was no response. He said that his regional manager hasn't heard from them so she will call again about the provisional refund. He said he would call me back. I have not heard from Citizens Bank since. I have not heard from XXXX XXXX at all. 

So I have been without my {$5900.00} since XXXX ( almost 7 months ) because of a mistake that XXXX XXXX made and Citizens has been unable to resolve the issue for me. There is no progress being made and they are not responding to me at all.