Try there parents email address saying something like "my sons account was hacked and his name changed"... etc... etc... If that doesn't work your probably not going to get your name back.
I've actually done this, and I got the name back within 45mins. I emailed [email protected] and said that my acc got hacked and the hacker changed my name so he could steal it
There was also forum thread for recovering names but I'm not sure if it still exist, atleast it did like 1.5month ago in account help section. However email is the best thing in my opinion