You can just write into Support and we can help you with this! We can remove the Facebook association and make sure you have a password to log into Chess.com with.
http://www.chess.com/forum/view/help-support/how-to-send-in-a-support-ticket
We also can deal with the abusers, members are not allowed to "name and shame" in the forums so I removed the screenshot you attached.
I have removed Facebook from your account, send me a message if you don't have a Chess.com password and I'll get you set up
Many users when loose starts to abuse my facebook account, which is linked with this site. How can make the link private!! One such disgusting example of a user who is abusing me :(