Unfortunately, Myspace accounts are hacked all the time, and really, there isn't much you can do about it, to my knowledge.
I haven't seen anyone really persue fixing it, as I have seen people just create a new one and begin fresh, if they choose to.
Unfortunately, the security over at the Myspace website is quite, porous. I myself can probally get through the security they have there, because from what I've seen, their not exactly very tight on security over there.
Usually, how it works is, when people modify their Myspace pages, they can use scripts and such that open up 'holes' in the security for their page, which then allows their page to be manipulated.
Sometimes, people are hacked because of well, easy passwords..
In any case, I'm sorry that it happened, and wish you the best of luck.