security deposit not paid

I hired a car for a week, picking it from East London airport. I dropped it on the 4th of November to their Vincent branch and told that I will pay R110 (collection fee) as I didn't return it to the original place. I am now struggling to get back the security deposit fee ever-since the car was returned on the 4th November, at times they will ask the RA number, if provided then they ask for ID number and the address. I am now told about the bank billing cycles after the 72hr that they promised has elapsed.