1. It is impossible for software to physically damage hardware. Your system broke probably due to normal use.
2. The box may say there will be downloadable content, but you are assuming that there never will be. There has been no official announcement to support this claim, and till that time, the box is not lying. That said, you must also consider that at the time the box was printed, there was clear plans for releasing DLCs on the Playstation, but the future of that is unknown. If they do end up not releasing any DLC, the box still isn't lying, as the box was printed before the hypothetical announcement.
3. Don't count on getting a refund through Bethesda.
It can damage the system. I took it too gamestation to be repaired and they said they have had several consoles in for the same reason. The way they explained it was when the game freezes its like driving a car and slamming on the brakes, it puts stress on the system and eventually if done enough, will break. Not to mention the fact that the PS was only 3 months old from new.
The chances of the downloadable content being brought out are slim to zero, either a definitve answer and date should be set for it release or they should stop beating around the bush and tell us its not happening. The fact that the game alone is still not running properly also warrants a refund. If I were to come round to your house and paint your bedroom but only do half of it and demand full price, surely you would not be satisfied and rufuse payment, if not, then you're a tool.