That really isn't the job of the counter agent -- the renter has the responsibility to ask questions if the rate is unclear.- They never went over the rental time / estimate costs.
The only rental companies that do this are the "budget" carriers like Enterprise Rent A Car -- Major chains don't worry about the little stuff and neither should you. I have rented hundreds of vehicles over the years from major firms and have never been charged for anything ding (and I never bothered to look at the car when I picked it up either...)- They never went around the car with me to point out dings so I was so stressed worrying about ones I noticed.
This is odd and not good. You might consider contacting Christopher Elliott, he is a colleague of mine and an expert at resolving issues like you seem to have had with this rental. He writes a Troubleshooter column and if you write to him, I bet he can assist.- They were hard to pin down on the phone.