FNB CREDIT CARD ***** - WHO IS TO BLAME

I recently experienced ***** on my FNB credit card . On the evening of the 29 April I got a sms that I had purchased an air ticket on my credit card for R 32095.89. I immediately called the bank to dispute the transaction and logged it with the ***** department , The amount was not yet debited to my account, but I flagged it as a ***** . 3 Days later the amount was debited. FNB ***** is a faceless / no accountable division of the bank. They refuted my claim saying it was no fault of the bank . Further the card used was stopped in February this year , so how is this possible ? I don't believe they even investigated this .