How can I block someone?
In order to block a user from messaging you, open their private chat, find the three dots on the upper right corner of the screen -> more -> Block .
Unblocking
If you change your mind and wish to unblock a user, go to Settings by clicking the Gear on the upper right corner, scroll to -> Blocked -> Hit the X to Unblock.
More
Blocked users can see your posts but they can’t send you a message.