Money just deducted from my account

I have hired a car from Bidvest Grand Central. I have received pathetic service. I kept asking for an invoice and never received a proper answer. R5500 has now been deducted from my account!!!! there was a small scratch on the car that I did not even do. And it should have been communicated to me about the amount to be deducted. they charged me +- R3000 for this. I did take a super cover . how car i pay this much for a scratch??????