Product: Money transfer, virtual currency, or money service

The Bank of Oklahoma cashed a check which was stolen from me in the mail. I have been trying to get my money back for the past few months, but no one has been helpful. 

Here is the situation : I used to rent an apartment in XXXX, Pennsylvania from XXXX XXXX XXXX. I moved out end of XX/XX/year>. XXXX XXXX XXXX mailed me a check for my rental deposit refund for {$1100.00}. 
I never received the check. 
When I emailed XXXX XXXX XXXX about it, I was notified that the check was already cashed. 
XXXX XXXX XXXX sent me a scan of the cashed check from the clearing house. I could tell immediately that the check was cashed by someone else. The checked was cashed by a " XXXX XXXX XXXX XXXX ''. Please see attached for this scan. You can see clearly that the check was addressed to me in XXXX. 
The check was originally issued by XXXX XXXX Bank in XXXX, New York. I was able to find this bank online and call them. XXXX XXXX Bank was able to find out that Bank of Oklahoma cashed the check. 
Then, I was initially told that XXXX XXXX XXXX was to work with the XXXX banks to get my money back. 
However, months have gone by without updates. I emailed a few times but no one would give me an update or details. 
Finally, last month, XXXX XXXX XXXX contacted me saying that they would not further pursue this matter. They said this was a case between the banks and me. 
I have never been told which Bank of Oklahoma the check was cashed at, so I didn't know how to reach out to them. 
So I reached out to XXXX XXXX Bank ( XXXX ) again regarding this. The senior security XXXX at XXXX has been helpful. 
It was only when I reached out this time that XXXX sent me an affidavit from Bank of Oklahoma. The affidavit was to state that someone else that is not me cashed the check. 
I signed the affidavit immediately and sent it back. 
However, now, the Bank of Oklahoma is requesting a notarized version of the affidavit. 
I am going to get a signed affidavit notarized to send it back this week. 
However, in the most recent email from XXXX financial XXXX, they did not seem optimistic that they would be able to get this resolved. 
It has been a few months now. 
I live in XXXX currently. I think the check was stolen somewhere in the mail between XXXX, Pennsylvania and XXXX, XXXX, XXXX. I suspect it happened on the XXXX side because I have received many other checks in the mail in XXXX XXXX ( including from the XXXX ). 
I tried to report this as a mail fraud, but never heard back. 
I'm thinking of filing a police report, but I don't even know where to file it, because it involves so many different geographical locations. 
This {$1100.00} is not a whole lot of money, but I want to pursue this because what happened was not right. I don't know if it involved some sort of organized crime. I don't want this to happen to other people. 
The banks and the rental company should have it figured out, but it's been many months. I thought the banks had insurance for this kind of things. Why can't Bank of Oklahoma refund me the money when they are the ones who cashed a check written to someone in XXXX?! 
Do you think you can help me please? 

Thanks very much. 

Sincerely, XXXX XXXX XXXX XXXX XXXX