Games not saving and saves world's erased

Major save issues: Single-player world will save more often than a couch co-op game will, but in both instances, saving is sporadic and unreliable. I can't trust the auto-save, and when I save-quit, the game either crashes or resets 3 out of 5 times. I've lost my world on more than one occasion; thankfully I'd been making copies of the game in case it became corrupt, due to these save issues. Today i turned on the box and both my world and the duplicate world are gone. I dont understand this. I see a lot of other people with this issue, and their tickets have been closed as Resolved. Clearly this isn't resolved... please advise. *No picture can be included. I'm sure you're familiar with what the crash looks like.