In order to block other users from mailing you, simply scroll to the bottom of their message, and click on Block User.
To unblock someone, simply scroll to the bottom of ANY message in your inbox (it does not have to be from this user), and click on �Blocked User List� to unblock them.
You'll know that you're blocked if you get a block message when you try to contact someone who has specifically blocked you. You can also be blocked from messaging users if you do not meet their messaging criteria shown at the bottom of their profile (ie age, gender) - these settings are found in Mail Settings.
Did this not address your issue? Try here...