There is not a lot that you can do at this point, unfortunately. If the email and password has been changed, and you are absolutely locked out of the account, WeeWorld is not likely to allow to to access it again (because "hackers" could pretend that their account was "hacked" to gain access to someone else's). 

For more information, check out the following articles. There are some tips you may find useful.
- How to: Hack-Proof Your Account
- How to: Get a Hacked Account Back