Hidden cost at Tempest car hire.

I've never felt so ******. I hired a car through Cartrawler/tempest car hire and paid a fee of R1500 for 6 days @R250 p/d. We made an extension for a further 7 days and we were quoted an amount of R1750, which was directly taken from my account. In total: a deposit R6340 was paid towards Europcar for liability and petrol (R4840 &R1500, respectively), R1500 towards cartrawler/tempest for 6 days and lastly R1750 towards tempest for 7 day extension. Once the deposit had to be returned, I received an amount of R4718; which means I was charged R3372 With that being said, tempest claims that the amount R1750 was not for the 7day rental, instead it was added towards the amount of R6340. Which infuriated me, because when we queried a rental for 7days we were told the amount would be R1750 and not R3372. NEVER USE TEMPEST!