Unauthorised debit orders

I am unhappy with the way FNB is conducting its business. Last month and this month (today) payments went off my cheque account to credit card without my approval or authorization. I made an arrangement to pay the amount requested, then suddenly my account is debited. This is not allowed and ********** as I didn't not authorize any of you to debit by cheque account for payments. I want this debit order reversed today and I will be reporting this matter to the Ombudsman. I called the call center and after holding on the line for more than 15minutes the person that was supposed to assist me just hung up on me. so unprofessional. I am really disappointed in the service.