YOU CAN'T EVEN CALL IT POOR SEVICE! NO service is more accurate

I paid R81 954.00, as full and final payment, on my credit card, on 17/11/2022. I also paid R 26 480 to clear my overdraft - also 17/11/2022. FNB Grahamstown gave me this amount. I paid it and heard nothing else. It was a bad time for me as my husband had died on the 8/11/2022. I did not insist on a settlement letter etc. NOW, I am told by Brooks and Luyt attorneys that I owe R12 000 on this account!!! I will pay it if necessary - but NOT before someone can give me a clear breakdown of my account! I have been trying to find out, for the past 3 months, how this amount suddenly appeared. I am promised by Brooks and Luyt that they will find out why I owe this money. I have spoken to at leasrt 3 people there - and I never hear anything constructive from them. I just have rude people refusing to listen to what I need. They are actually harrassing me now. I have phoned the credit card division (from an FNB branch - I was told that they will "escalate" the query -but I STILL I have no answer!!! I phoned the credit card division again today. I was tranferred to "collections". They couldn't help and I was transferred to debt review". I was cut off and phoned back. I was then told to send an email explaining my situation!! BUT - guess what - my email won't go through to the email address I was provided with! SO NOW WHAT???!!!