Extra charge with no invoice, explanation or response

I rented a car for one day from the Cape Town office on 28 Oct. when I returned it, they informed me that the hub cap was scratched. I told them I am not happy to accept liability as I only parked in 2 spaces, both of which were in a flat parking lot with no curb. They told me I have to sign the form anyway, but I can write on the form what I have told them which I did. I also emailed the head office as soon as I got home, explaining and requesting that they contact me. They never responded but an amount of close to R1000 came off my credit card the following week. No email notification, invoice, call or response was received. I find this very annoying. At the least I would have expected to receive an invoice in writing (is this not my right as a consumer?) and also a response to my email or concerns. If they really assessed the damage and could determine how recent it was or something showing that they even read my statement. I will not rent from Europcar again and I do not recommend them.