Product: Bank account or service

I filed a chargeback request for {$2500.00} that was sent for the purchase of goods that were never sent to me. I contacted the bank XXXX XXXX to file the chargeback which I was told would initially be resolved in a few days with the credit back to my account in under 5 business days. After that time elapsed I was told that it would take 10 business days which would have been XXXX XXXX. However when the credit did not present in my account at that date I was told that due to XXXX Day that it would n't be the 10th business day until XXXX XXXX which was incorrect because the bank did not observe XXXX as a bank holiday as I went into the bank that day and not only made a deposit and withdrawal with a teller in the bank they held regular business hours, which is the first violation of XXXX. XXXX On monday I called to inquire about the chargeback to be told that it was denied due to there being a refund given on XXXX XXXX for {$2400.00} ( not the same amount from the same vendor ). I explained that every time I called that if the back office ( that I was not allowed to directly speak to ) had any questions or needed any additional information to contact me, they did not. The reality is that in looking through my account they ASSUMED that because a PAYMENT not a CREDIT was made to my account from the same vendor that it was towards the {$2500.00} however not only are these amounts different which nullifies the argument that a refund was given. I was further told by a supervisor with the bank ( please verify with the recorded calls ) that they were told by the vendor that a refund was still PROCESSING which means it was never sent. I explained that had they simply contacted me as requested I could have explained the total amount paid was {$9600.00} which can be verified in the same account as a cashiers check was made to the same vendor for {$7100.00} in addition to the {$2500.00} which was sent electronically. I have proof to show that another payment was made to me electronically through another source however from the same vendor to settle the balance due, and that the REMAINING amount due was the initial {$2500.00} which was a deposit to be used towards the total balance of the goods. THAT amount has yet to be returned and this is in full violation of Reg E and the fiduciary agreement between myself, MB Financial, and XXXX respectively that dictates how chargebacks are to be handled. This is the equivalent of having multiple orders say for a company like XXXX XXXX for XXXX charges, say : {$300.00}, {$290.00}, {$300.00}, and {$280.00}. If a payment from XXXX XXXX presents itself for say {$280.00} and I file a chargeback for merchandise not received for {$300.00} is it the job of the bank to ASSUME that its a similar amount in a similar span of time so its a refund? That is pure craziness when a person 's monies are concerned and an outright oversight and pure carelessness on behalf of the bank. The same would be if a deposit for say {$50000.00} presented in my account to which I knew I did n't make the deposit nor anyone else, so I assumed there were my funds, should I be punished with potential overdrafts a debt due to the bank to return said funds? Based on the same logic I could simply just assume that monies were mine.