Product: Checking or savings account

On XX/XX/year>, I received XXXX charges to my Bank of America account for a total of {$16000.00}, sent via online XXXX XXXX to a XXXX XXXX XXXX account through Bank of America. I filed a fraud report with Bank of America and have since been fighting to get my money back. 
I have provided copious amounts of evidence that show the transaction was not initiated by myself or by my XXXX employee at my store, including gate and alarm logs from my business that show that nobody entered or left the premises hours before or after these transactions took place. I also have NEVER used XXXX XXXX in my life, and yet these XXXX transactions were sent through XXXX XXXX. Now the bank has XXXX access to the XXXX XXXX  function on my account ( without mentioning that they were doing so, nonetheless ) - why is my XXXX XXXX function now deactivated if the bank is claiming the transactions are legitimate? Next, each of the transactions is for a complete whole number with XXXX cents - {$4200.00}, {$4700.00}, and {$7500.00} - when do credit card payments come out to such complete whole numbers? Maybe XXXX, but all three? As well, the XXXX transaction line items on my statement are completely different than every other XXXX transaction that has show up on my account. For reference, the XXXX fraudulent charges have no identification numbers or details provided. I have mentioned all of this information multiple times and it has been completely ignored. 
Per BOA request, I hired an IT expert to scan all three of the computers at my store, but the scans did not find any conclusive evidence of tampering. Because of this, Bank of America has chosen to disregard all of the above information ; when I continued to push back, Bank of America told me I was not being reimbursed because of the conclusive evidence that the XXXX address for the transaction was consistent with those of past transactions from my gallery. When I promptly proved to them that the transaction was through an XXXX address associated with XXXX XXXX XXXX  ( I have XXXX at my store ), they then did a complete XXXX on the narrative, claiming that the XXXX address actually wasn't of importance. Now they are stating that an Authorization Hub ID number points to XXXX of my devices being used at the store, but they can't give me information other than that the device runs XXXX XXXX - I have XXXX computers at my store, XXXX with XXXX XXXX and XXXX with XXXX XXXX. The " legitimate transactions from the same device '' that the bank refers to came from the computer with XXXX XXXX, not XXXX XXXX. The list goes on and on and on. 
I have trusted Bank of America with my business for over 30 years, yet now they pursue this fraud claim saying I am guilty until proven innocent. Well, I have proven my innocence, but they continue to attempt to work around this with pitiful correspondence, inaccurate information, and vague explanations. 
I have now spent dozens of hours, hired an XXXX XXXXXXXX and recently a forensic accountant - the forensic accountant is now suggesting legal action - all of this is ( and will continue to be ) at my expense. 
I am simply at a loss, but I will be shouting my story from the rooftops until BOA does the right thing. XXXX