Economy car rental unsatisfactory service and advise.

I recently wanted to rent a car at Cape Town airport and gave Economy the deposit of R691, they advised me that I needed to pay another R600 at the desk in cape town. Upon arrival i then found out that they required a R14000 deposit which wasent mentioned to me on order. I didnt have the credit available in my credit card and couldnt take the car. Economy Car rental then told me they wont give my deposit back. They are based in Greece and dont have a telephone number in South Africa which I find very strange at the least. I then got another car from Avis where they only take a R2400 deposit and the service is excellent.