Abis car rental deducted twice

I need help , I have hired a car in December 2019 and returned it in January under my business account through Flight centre Agent. I collected and returned the car in PE Airport in good manner as agreed. few days later I had a minus R7700.00+ in my FNB account which I enquired with FNB and was told I should contact AVIS I had numerous visits, calls to AVIS spoke to Charles and Nadia till to date no one has ever be able to help me.

Could please resolve this matter as a matter of urgeny, the money deducted was meant for another obligation which am struggling to fullfil its been Months now with no communication of an update whatsoever