Ad service from fnb who won't refund me my money of a paid up loan

I have been banking with fnb for more than 10 years. Early this year tbey offered me 2 personal loan which both amounted to R15 000. I paid the monthly installments until Nobember when they didnt debit. An arrangement was made that I would pay the arrears in 2 months. I resigned in November and advised fnb that my in that month I will only get paid at tje end of November so they should debit then not on the 23. To my surprise on the23 fnb debited my account. I called them and revered the transaction and rearranged as per initial arrangement. December the 14th fnb debited my account 4 times. On the 20th fnb debited my account again. I queried that with them and they promised to refund me the over payments and sent me an email after I have called them numerous time requesting a refund. I kept going to the Khayelitsha branch and I was sent from pillar to post. The consultant couldn't help me. The next day I went in to call the loans department since my airtime got depleted from waiting 30 mins to receive service. I was at at the bank for 45mins before I could gegt help. I was promised by 2 consultants on the phone that the team leader has escalated the matter and i would be paid on the same day if not early the next day. Its been a week and I am still waiting for my money. The other consultant told me to wait 5 to 7 working days to receive my money back. I am so disappointed with the service and inconvenience i received from fnb as a matter of fact after my refund i am changing banks!