Rented a car for a day with Avis in Zagreb on a rate $40 and turned it in without getting a receipt because we had a flight to catch and it was after hours (that was what we were told to do). Got charged an additional $180. The receipt just says "additional services." I stopped by the counter a week later and the CS agent said someone dented the door but Avis has so far failed to provide me with either a letter to that effect or any proof of damage (photos, etc.) despite multiple emails. Should I dispute the charge (Chase) or just go to Chase for insurance? Advice please!!