Product: Checking or savings account

Hi, I tried to purchase an XXXX laptop at the XXXX  store located at XXXX XXXX XXXX XXXX, XXXX XXXX. It was on XX/XX/2015. The laptop 's price was {$380.00}, including taxes. When I swiped my Bank of America debit card at the check-out, it was declined. I tried again with my debit card and also Bank of America Credit card. After a few times the cards were declined, I called Bank of America to check reason for decline. The Bank representative on the phone told me that they might have got declined suspecting suspicious transactions. He asked me to swipe the card once when I was still on the call and he would approve it. I swiped the the Credit Card and it was accepted once and a receipt was generated. But there were no receipts generated for my Debit card swipes. We went on international travel the next day and came back after 4-5 weeks. We couldnt check the statements while we were abroad. A few days after coming back to our home, when I checked my debit card statement I found 2 transactions on the debit card on the same date at XXXX, which is in addition to the transaction I have on my Credit Card statement. These 2 extra transactions posted on Debit card were for {$410.00} and {$380.00}. I went to a Bank of America branch in person, and they told me to contact XXXX store itself for a refund. They simple declined to help in this issue, saying they can not help with older transactions. These spurious unauthorized transactions totaled {$790.00} I went to the store multiple times and the store manager told they don't save receipts which are older than 30 days. She told, she can refund the money only if I get the copy for this transaction. But, there was not a " copy of receipt '' for my Debit Card transaction since there was no receipt generated. They didn't guide me in the proper direction too. I called the XXXX customer care at XXXX, multiple times. Every time, they would create a separate service request number only to close those later, saying they could only see a single transaction on my credit card and there were no debit card transactions on their end. One of the service request numbers is XXXX. 

One of the customer care representatives sent an email to XXXX, copying me in the email a well, asking for explanation on my extra transactions. The reference number quoted on email was XXXX. In the email, I attached the credit card statement showing the right transaction and also the debit card statement showing XXXX wrong transactions. 
In response, they again acknowledged only the single credit card transaction and told they dont see any transactions on their side from my debit card. 

I really don't know how to get my money back. I have lost close to XXXX $ for no mistake of mine. 
I want to highlight that, Bank of America has not helped me in this process. I still feel that the bank also has to come up with an explanation of where my XXXX $ is. 

It took such a long and arduous process and spent so much of time on this for over 3 months with no resolution. 
I will be very grateful, if you can help mediate between XXXX and Bank of America on these unauthorized transactions and help me get my XXXX $ back. 

I am attaching the credit card statement, debit card statement, original receipt from XXXX, Copy of email exchanges with XXXX customer support. 

I am not sure who is the right company to handle this issue. If I have to file a complaint separately on XXXX, please let me know.