Incorrect amount collected by FNB

I have been a cluebt of FNB since 2007 but im appalled on the manner that their credit card collections department works. Last month i got a call from their collections department regarding repayments on my credit card, i spoke to an agent by tge name of Bongani we had an agreement that i would be able to pay R2071 as an arranged payment which was debited on the 28th March. Last week i had funds that were paid into my account and an amount of R7380 was debited and i got an sms that it was as arranged with the agent which was not true. We had not made that kibd of arrangement only one arrangement was made. This is not whar Treating customers fairly is about especially if I had honoured the first arranged amount. This agent is very selfish in his conduct as he is only concerned about the commission that he will get paid. I would like FNB to pls rectify this and reverse the amount. My arrangement is to make payments of R2071. Please take ur consultants for proper training, the second arrangement is a ********** one done by the agent without my knowledge. I would like the call recording as well because i know he and i never made such an agreement.