Someone created a battle.net account with my e-mail, need help.

I wanted to try out Diablo 3 so I went to create a battle.net acct and it said my e-mail was already associated with one. I have never used battle.net so I thought this was a mistake. I searched my e-mail and found out that in July of last year someone named Zhang created an account with my e-mail. I'm not sure if he was able to verify the account or what and I don't know if this should be a concern at all for me. Also I am not quite sure how to resolve the issue. Any help would be appreciated, thanks.