Payment arrears for non-existing facility

So about a year ago I had a revolving credit facility. I closed it out and have confirmed with the Revolving Facility department that the account is settled and closed. Now I get SMS's at least twice a month and automated phone calls sometimes up to 5 times a day (lately the phone just rings and then hangs up after a few seconds when I answer). I phoned the number that does that this morning and spoke to the department again, the lady confirmed that the account is closed and when I asked why I keep getting "Payment in Arrears" notifications she hung up the phone.

Furthermore, I get penalised at the end of every month with two R69 rand payments that go off my account for the closed facility that are then payed back a few days later.

I am not sure what is going on with FNB or how this is even possible. I just know it is very frustrating and if they can't be trusted to take care of such a small matter I really do not feel confident keeping my money with them.

Not sure what I need to do about this but I am really annoyed at this point.