fnb makeing unathorised changes on my account

I have been on the phone with FNB for the last week trying to solve 4 issues for this month alone. i was finally solved but will most likely be the same issue next month. Interest was charged to my credit card even though i settle it every month. when contacted by your call center it was said that my settlement date was changed. this was done without notifying me. FNB is costing me way too much money and not solving my problems. please pay out all my investments as soon as possible and close my account. i have already opened a discovery bank account.