Disappointed in how the charges were handled.

I was very upset to learn that even though I'd prepaid for my reservation and was told I'd not owe anything at the time of the pickup, I still had over $300 charged to my credit card (not a hold, but an actual charge). When i called Fox to clarify, I was on hold almost an hour before getting through, and when I did I was told it was a deposit on hold because Fox had not received payment from Easyrentcars...the deposit would be credited back when I returned the car. It was credited, but i was charged in essence 14 days of interest on $300 because of the charge. Luckily I had the credit available on my card but this could have been a very bad experience and still shouldn't have been the case since I was charged upfront and prepaid over $500 for the rental. Very disappointed in this.