FNB Credit Card ***** Line

I got a message from my fnb app saying that R14k was used in a purchase. First thing I did was logged a ***** case as I had made no such purchase. The details of the purchase were from a credit card that had not been delivered to me from FNB and the status of the card on the system at the time of purchase was inactive. I received no pop up to decline or accept any purchase on the app either. I consistently called the ***** line to follow up on the case. After a month they decided that they didn't do anything wrong and am now liable for all the debt that was incurred on a card that I did not have in my possession, with a status of inactive. FNB has essentially ****** 14k from me and I am now accumulating interest on a purchase I never did