Stardust, If you delete your profiles from the manage profiles page, it will only delete the actual profiles. Any listings that you have created using these profiles prior to deleting them will NOT be affected.
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 .