BuddyPress.org

This is more a WP question, you can remove the comments by passing an empty array back to comment form in the template file, have a read of this post on WP support:
https://wordpress.org/support/topic/remove-markup-notes-from-below-twenty-twelve-comments-box

P.S. when you state you have tried something please actually say what it was you tried as it may have a bearing on the matter.