Disappointed with african Bank

I am highly disappointed with the service i received from african bank,They come and go into my bank account as they please and still have the audacity to tell me that they can not reverse funds taken from my bank account even though its not the agreed amount and its not the right date.Money was paid into my account yesterday and african bank took just more than half of the amount and when i called them to enquire their customer care informed that they can not assist me even though the money debited was not my salary and the date was just a random date. Apparently even if you make an arrangements with consultants telephonically to pay an instalment less than than the agreed amount they will still track your account for the initial amount you agreed to pay when you signed the contract with them. So i just don't understand why they even have a customer care line. I am really really disappointed