Car Hire Fraudsters

I hired a White Nissan Hardbody on 19th December 2017 from a company called "The Rental Boss " based in Fourways, with the expectation of returning in on 27th December 2017. However, before I could take the car I was required to pay 6000 rand deposit and pay for the days that I expected to rent the car at a rate of 600 rands per day in advance in all I had to pay 10900 rands before getting the car. I finished my trip early and wanted to return the car on 24th December, however the office emergency number was not working , the office landline and cellphone were also not working. There was no way of communicating with this company. I eventually got hold of someone on the 27th December and arranged for the car to be dropped. I then expected a full refund of my 6000 rand deposit since there was not incident no accident no fault while the car was in my care. I also expected to recieve a refund for the days that I did not use the car (between 24th - 27th December 2017). What happens instead, is that they deduct 3000 rand from my deposit and only pay me back 3000 rand and I dont even get refunded for the days I didnt use the car. This to me is day light robbery, these are scumbags. I believe I was exploited simply because I am not south african, made to pay for the hire in advance and on top of that I didnt even get my whole deposit yet I was assured I would get it back in full. Someone needs to investigate these guys. They are a bunch of crooks who take advantage of honest gainfully working foreigners living in south africa. Can someone please help.....I am extremely frustrated and dont know what legal recourse to follow. I NEED TO GET MY MONEY BACK...