Go to "Rick at Informed Athlete" - his blog may reveal the information you need. Also, he'll do a consultation call to help determine the next step. Rick is a member on this site and periodically checks in.
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 .