FNB took money instead of a refund on their fees

They deducted a rebate from my account and the online secure chat banker said that they reduced my credit fee for having a positive balance. So why did they take the money from my account and not give me the rebate. Then secondly the banker that was chatting to me took more than 30 minutes to respond after we started chatting by that time the chat was closed and now I have to wait in the queue again to get to the same point. Any assistance will be helpful.