My account has been hacked. I changed the password, but I cannot log in while the hacker is still online (tried, failed), and neither can I disconnect him via this site, because an error occurs.
Please contact Support immediately by filing a ticket through the “Ask a Question” tab on that linked page. They will be able to assist you. If you have a ticket in the system about this, please update it to ask your questions.
For tips on what information to provide in a ticket, please read this post.