Deposit not returned

I hired a car for three day and returned on the third, luckily I took tyre cover, when I returned it it had a nail si I filled in the accidental report for the nail. I received my R2000 rands for fuel 4 days after returning the car but I haven't received the R3500 deposit after 10 working days. When I called to query the situation the told me about the damage of which I told them it had nothing to do with my deposit since it was under tyre warranty. It's not the first time I'm running into difficulties and I will never hire with them again.