FNB ; the bully bank

I have a FNB card which I was given by FNB when my previous company was a FNB client. I rarely, if ever use the card but there is a long outstanding balance which I serve monthly. Not using the card, I cut the card into pieces and threw it away. I receive a call from FNB three weeks ago stating that I have missed a payment and that I needed to rectify the matter - I obviously agreed. The stated that they would send a letter to confirm this arrangement, which they duly did. We tried to pay the agreed payment into the account stated on the letter but could not access the account - it kept on stating that the account was incorrect. A week later FNB sent me an unbelievably threatening letter stating that they were now going to blacklist me as well as submit my details to Credit Bureaus etc. which would disallow me from ever again obtain any form of finance from practically any institution. I then went to the FNB Brooklyn branch in order to seek assistance so that I can settle the two payments due. The most helpful branch immediately identified that the account number on the FNB threaten letter was incorrect. He gave me the new number and we were able to make payment immediately. The short and long of my experience with FNB is that if you need a partner bank, go elsewhere; if you need a bank that bully - go FNB!