Hi, sorry for your issue. I believe it's a limitation of the Facebook login extension. You can either create a new user and I think I can migrate your posts (only posts) or another thing is that I can try to change your password on the admin module. Please PM with your suggestion (and new email if applicable).
update: users that remove the facebook link should reset the password afterwards to access the board. After that you should be able to do whatever you need.
