If you're not the original owner, then there nothing you can do about it. You can report the account by calling blizzard up, they'd lock the account until the original owner provides a REAL photo I.D or birth certificate sent in by Fax or Postage. On that point, they don't accept digital information, only real proof of ownership (things as I mentioned above)
FYI: Blizzard will only listen to you if you can provide, secret question, User name , email , phone number, and depending on the Blizzard agent you talk too,sometimes you'll need the CD key.