Forrest check out the subscriber part of this post it might fix you up Enable Comments and Subscibers Help!

A visitor to your website has signed up as a user. Pay attention to the email addresses though. Sometimes I get people with .ru addresses. They are from Russia. Not a bad thing but highly unlikely to do you any good if you run a mail campaign to those addresses.

Forrest

If they have hacked your page your best bet is to log in a change all the passwords on your admin and personal account.

Also if you see any new accounts that you have no knowledge of delete them.

That what I would do.

Percy