Thanks for responding, everyone. I have contacted Hertz both in the US and Croatia and disputed the CC charges. I do have copies of the damage report and everything else (except, unfortunately, pictures of the car when it was picked up). There were only two guys working when I returned the car and neither was a manager (and I had a flight to catch), so taking this to a higher level at the time didn't seem to be an option. The charge was ~$300.