Dollar Rent a Car DTG Operations Told of damage to the car after return when damage did not exist. Daytona Beach, Florida

I rented a car for 4 days at Daytona Beach Airport, a small facility that does not have someone check the car over when you take it nor when you return it.  I got the keys from a desk clerk who started off friendly, then quickly changed to borderline rude when I declined prepaying for gas, prepaying for toll roads and refused their insurance.  She made a point of telling me she had a friend who recently incurred a $1600 charge because something happened to the car she rented and her insurance didn't cover it.  Upon refusing these add-ons, she flung the keys on the desk and said "the car is in space E19".  The whole ordeal took 1/2 hour with only one other person ahead of me.  I rented a Ford Fusion and in E19 which was the furthest space in the row was a Ford Focus.  I walked back down the row and saw a silver Fusion as had been noted on the key in space E2, tried the key and sure enough that was my car. 

The purpose of my trip was to visit my mother and sister and the car was carefully parked only in their driveways where no damages could have been done.  It was driven very few miles and less than 3 gallons of gas had to be replaced upon return.  When returning, you merely park the car in one of their spaces and bring the keys and gas receipt inside.  No one checks the car over.  I returned the car, caught my flight home and upon arrival home in GA, had a phone message from Dollar saying there was a big dent in the rear passenger door and they need me to give them my insurance information and claim number.  I called them immediately and said it's impossible that the car was damaged while in my possession.  I am wondering how many times they contact people after they leave the state knowing there's no way to dispute the damage and knowing insurance companies won't send an adjuster and just mail them a check.  It will cost me either the amount of my insurance deductible or if I don't file a claim, I'm sure they'll put a charge on my credit card for "repairs" which I don't believe exist.