lightning returns keeps crashing?

I bought lightning return brand new from game for xbox 360. Took it home and it wouldn't load. I cleaned it and tried again, then made some free space and tried again, then updated my system and tried again and it worked-sort of. It crashed after about half an hour into the game. I reset it and it took a few more attempts to get it to load, then crashed again in the middle of a battle. Annoyed, I took it back and went and bought another brand new copy, this time from hmv. Same issue. So two completely different discs, both brand new, both not working. And before you say my xbox is faulty-every single one of my other games works perfectly. I'm completely stumped, and still waiting on a return email from square enix. Help?!