Blocked users have been removed from the group by an admin or moderator. They will not be able to rejoin and sell in the group unless they are unblocked.
Blocked users will receive an error message when they attempt to join a group that they’ve been blocked from.
Admins can unblock blocked users and allow them to re-join the group and add listings to group again.
To do so, tap on the ‘unblock’ button beside the user profile that you wish to unblock in the list of "Blocked Users".