Bad Service with reversal after settling account

I settled my Standard Bank Vehicle Finance account in April and the bank still deducted from my account. The bank owes me more than R4000 and now I have some unpaid bills because of them and they said they will do it by the 14th of May. The service I received is totally pathetic, their systems are pathetic because they can't reverse my money. I am fed up and still waiting for my money. I am disappointed after banking with Standard Bank for many years. I am changing banks after they reverse my money!!