Double Bebit without permision

Hi my name is Schalk, I have been a FNB customer for a long time, my acc was debited twice in one month for the same loan, when I called them this morning to rectify it they flat out refused to assit and said they can't reverse the second payment, I payed my instalment on the 18th R1500 and odd and now today they decided to debit an amount off R2600 and odd. I told them they need to assist as it is money that I need to pay my rent with!!! They just transfered me from one person to another for an hour long. And then said NO! I have had it! Slogan should read FNB HOW CAN WE GET YOU TO SWITCH AND THEN ROB YOU! I am moving back to STD Bank today! I am also seeing the finacial ombudsman today to see if they can assist. This is now the second time FNB refused to assist me.