Account of my mom has been hacked, password changed, alternate email changed and security question changed.

The account of my mom has been hacked last week. 

Yesterday, our family has been a victim of fraud by those hackers. No doubt about it. They read all the emails of my mom and tried to fraud us with all the informations collected from the emails.

What can we do to close permanently the account?

Thank you very much for your time, we're all a bit freak out about it...