If you harass someone, whether through comments or private messages, that person can report those specific messages to Facebook staff, who then reviews every case. All reports are anonymous, so you will never be told who flagged your content as abusive. read more
Learn more about what happens when you block messages from someone. Report a threatening message. Note: If you want to report a secret conversation, follow these separate instructions; Ignore the conversation. Delete the conversation. Keep in mind that this won't delete the conversation from their inbox. If you want to report the conversation, take a screenshot before you delete it. Block them on Facebook. read more
Only your Facebook friends can contact you through Facebook chat or post on your timeline. Block the person. This will prevent the person from adding you as a friend and viewing things you share on your timeline. Report the person or any abusive things they post. read more