Last name change dilemma

Im from Ohio, but my divorce was in indiana when i lived there... my question is this...when we were in court my ex-wife requested that her last name be changed back to her maiden name and the judge said that was fine and even called her by it. since then she has been re-married and curent ly going through a divorce with him, but heres the catch she is still using my last name, and even has a checking account using it. she even still uses it in her e-mail.
Is there anything i can do to get her to change it??

no. she can use any last name she wants as long as she is not committing fraud by use of the name.