Apple ID verification failed

Recently i've been noticing app purchases using my apple id and some of my informations were changed.as soon as i've learned of this i went ahead and changed my apple id password.I was able to do that but everytime i try to log back in, it asks me to verify the account,i go through the motion and enter the verification code and it comes back stating " this email is already associated with another account" that's it. it won't let me go any further. What can i do??

thanks