.....would cover the phone due to the same condition. Thermal fractures due to leaving a phone in a hot car is not a manufacturer defect, nor is damaging it while carrying the phone in your back pocket, getting the phone wet, dropping the phone, running it over with your car, etc.
It is considered user damage. You are barking up the wrong tree in this case. You have to take responsibility in this case. You should be happy they offered anything toward replacement/repair.
When I dropped my Samsung S4 and cracked the screen, I didn't complain to Verizon or Samsung. I simply did an insurance claim and got a new phone. Did you even have phone insurance ??
It was time to upgrade my phone, so after looking at the different phones available, I settled on the HTC One. The phone fit my needs, so bought 2, one for my wife, one for myself. After 4 months the screen completly shattered. I always leave my phones in my cars if I am going in somewhere that I won't be using the phone, have done so for years. I left it in my truck one night, in my garage, and in the morning on the way to the gym, made a call, and set it on the seat as I went to my workout. When I came back out, the outside temperature had warmed up about 20 degrees, and the temp inside the vehicle stayed as warm as it was when the heater was on. The glass had no chips, nor had it been abused in any way. The screen wasn't just cracked, but the entire surface was crackled like the rear widow of a car when it thermal fractures. I checked with my carrier, and the said it would be an issue that HTC would have to resolve, and in fact this was not the first HTC one that had done this. I called HTC, and the charge was going to be $180 if I wanted it fixed. Not because they don't fix screens, but because it was left in my car, and they don't cover thermal fractures. If fact they don't warrant issues that occur from carrying the phone in your pocket, or if you leave in your vehicle. With this being the case, you have to assume the only acceptable way to handle the HTC one, is by carrying it in your hand at all times. They deny that they have been having issues with the screen, but coincidently they now offer free replacement if your screen gets damaged during the first 6 months of ownership for the HTC one purchased since February 18th, 2014. This is a very unusual promotion for a phone they say they have not been having screen issues with. Don't be fooled, there are limitations even to this promotion. I would strongly suggest that you Google "HTC one screen issues" and see just how many people are having these problems, and perhaps you might want to consider a different company.