He has no credit card information. His account is canceled already so he can't tell them that he's canceling it to prove it's his. He bought the game from NCSoft online so he can't get his serial code. He doesn't remember his old email address that has the unique account ID.
I can't think of anything else. Unless naming his characters on his main server would be enough (he only knows the level for 1 of them).
Ideas?