Complaint Review: Enterprise car rental

I had a rental through my insurance company, while my car was being repaired, when I picked up the rental vehicle it was parked with a car on each side and not even enough room to walk around it, a black prius which was filthy dirty the agent quickly walked around the vehicle pointed out rear bumper scratch which was noted. I returned the vehicle on Friday afternoon to the auto body shop in Wilton CT, and I received a call today from Enterprise stating that I returned the vehicle damaged. I know for a fact there was no possible way this car was damaged while in my possession. when I asked what the damage was they stated the passenger side rocker was damaged. I had no idea what this was, she then explained to me what part of the car this was. I checked the car when I left it at the auto shop and did not see any damage to the car. I then asked how would this type of damage be caused. she said it can be caused by riding over a curb or side walk!!! really I think I would of remember that. I am so disgusted with this, do I have any were else I can go for help. Enterprise has been no help from the assitant manger to the Enterprise dispute line no one cares about my side of this and I am the one who has to pay for damage I did not do to the car, I have asked them for a photo of the car and they tell me they don't have access to that, what can I do?