AVIS are *******

So my insurance rented a car for me at Avis in June 2018, the car I got had dents and scratches on it already when I got it. When I returned the car I was told that it is as I got it but later on when they were supposed to return the deposit of R1400 they did not and I called to ask why but the manager had stories and kept dodging my calls. They did not return my money and I then decided to let it go because their customer service was just as useless. The insurance rented a car for me again on September 29th 2018 and I returned it on the 29th October. I AGAIN request for the person that checked the car when I took it to come check it again and made it clear to him that they took my money with no reason. He checked the car and said that all is well AGAIN. I paid R2000 deposit this time around and the money they're returning to me is R1199,19 and I have no idea why because on the invoice they sent me it doesn't show where the money goes to, only shows what's due to me. Avis people are *******, they find any way to knock you. When I left the car at the airport they said I'll get all my money back but that again did not happen. I'm really not letting this go this time around, I'm honestly getting a lawyer so I can get my first deposit ad well.