Complaint Review: National Rental Car

Returned my National Rental Car in Baltimore without damage.  About an hour later I get a call indicating the car was now damaged.  I told them I didn't do it.  The person at that point told me everything was fine and they would not be pursuing it. 

Two months later I get a letter from National Rental Car indicting there was $718 damage and they want to know how I will pay them.  I called their claim department and again indicated I didn't do it when I left a phone message as their adjusting did not pick up. 

I made an additional attempt to call them back at which point I told them again that I didn't do it.  As the conversation progressed, the agent suggested I turn it into my insurance and I said "Again, I didn't do it, why would I do that, its not Obamacare free for everyone; It ends up costing me if I file a claim".  THE NATIONAL RENTAL CAR AGENT THEN CALLED ME A "RACIST" AND HUNG UP ON ME.