National Car Rental

This is a sketchy place and the bad news is if you want to rent a car in Thompson, this is pretty much the only choice. I went there and rented a car for a day trip (business). At the counter, the guys were very nice. Upon return home, I got an email saying there is a damage on the windshield and they sent me two pictures. I started to think where had I been during the day and when that could happen and I had no clue. Thompson is a small town and my whole day rental drove about 40KM total and it's all in town, max 50k/hr except a little bit highway driving from the airport. Then I had another look at the photos they sent and the damage is a small ding on the driver side windshield, close to top corner, on the black trim which is very hard to notice even with the photo they sent. I'm not saying this is their fault, it's my fault missed the damage after I got the key, but another thing jumped in my mind is at the time of picking up the key and did all the paper work at counter, one guy gave another set of key to the guy I was dealing with and there was already a set of keys assigned with my paper work, they didn't say too much about it, just looked at each other. No one would picked up that detail until I got email about the windshield damage. From all the rental places, they know who's coming, what kind of car they are renting and which car they are going to get. The keys are normally sit right on top or right beside the paper work for that person. and now I started to think why they changed the keys for my rental?? Anyway, there is damage on the car, I had no argument about it, so I let my insurance company to handle the rest. Now, it's been well over 2 months and my insurance company is still waiting for final repair bill to pay them and close the case, a few tries from my end and still no luck. I wasn't going to leave any positive feedback at the beginning but the way they handled this issue is really unacceptable.