Abused client, African bank doesn't want to close paid up credit card

I have a very bad experience with African bank, they've been financially abusing for a long time now. I had credit card with them, I once reported them to hello Peter because I was paying the credit card but the balance wasn't going down, then after reporting them they handed my account to lawyers, which I did settle the credit credit card with the lawyers and settlement paid up letter was issued to me by the lawyers, I then submitted all the necessary documents requesting for the account to be closed but african bank doesn't want to close the account, I've called them countless times requesting that they close the account but they don't want to close the account, instead they are abusing my rights as a client, African bank can you please close that credit card as I have paid it now, stop abusing your clients