User blocking
All registered profiles are public, so you can send a message to any member of the community. For the same reason, any user can write to you. However, if your interlocutor behaves unacceptably, you can block him (add to the “black list”).
To do this, in the upper right corner of the chat with the user you want to block, click on the 
symbol and select “Block user”. After that, neither you nor the interlocutor will be able to write to each other.
symbol and select “Block user”. After that, neither you nor the interlocutor will be able to write to each other.
To unblock, repeat the steps above and select “Unblock user”.