Try driving a flat blade screwdriver in the slot to open up the splines. You also might have to persuade the joint off the splines with a mallet or brass drift.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .