FNB how can we help you slogan is B.S.

I am unhappy with service I received. I called Fnb 6 Jan 2020 Monday to get my settlement amount for my credit card and they told me I need to pay R8845 which I did and called again on Tuesday to confirm if all was in order. I was told all is in order and I paid over by R250. When I paid the settlement was calculated based on the condition that I pay with 3 days. I did my part and when I submitted the application to close my card, they added additional charges and now they do not want to refund my R250. I tried reaching them by mail, twitter and telephone and my matter has not been attended to.