I've been meaning to get a memory stick for a while now, though every time I go to the store I forget to pick one up. So no, I've got no way to restore the account.
Whoops, sorry your save got corrupted. I would suggest you make it a high priority to get at least two memory sticks. You definitely want a backup of your main accounts. It's rubbish that we have to backup (never done it before), but it better to be safe than sorry. If only we knew what caused the corruption, and hence, how to avoid it.
It deleted itself actually, the profile started up like I had never played the game before. No error message or nothing. It was just gone from the hard drive, Batman arkham asylum did the same thing to me one time. The weird part was I was just in the main menu trying to look at the stuff I had unlocked.