This whole C&P is in reference to a text message coming from a fraudulent account on Facebook, but you may still find parts of it useful.
1) Report the account that sent the text message to Facebook as either a scam/spam message or a fake account.
2) Do not accept friend requests from people you do not know and have no mutual friends with.
3) Go into your privacy settings. Hide your email address, phone number, and friends list. This will stop any unwanted calls from this source, reduce your chances of being hacked, and limit the victimization of your friends.