Not returning funds as said

On the 24th of July 2015 I took out a courtesy with avis centurion due to my accident I was in with my vehicle, they billed me an amount of R1250 as they said it's a deposit I have to pay before taking the vehicle, then on the 3rd of August 2015 I returned the vehicle due to my insurance paying out from there they had said they will release my funds within 4-5 working days I haven't received those funds I have called them numerous times talking to different agents and all I get is the same excuse saying they will pay to know where my funds are, ontop of that they deducted R456. 10 from the deposit but now it has added on which makes it R1706. 10 I'm very disappointed, unhappy and disgusted that a company of this many will not just literally release my funds back into my account cause they very fast in taking the money but releasing it is so difficult.