You can block messages from someone in Google Messages.
Important: If your Google Messages for web syncs with Google Fi, use the Android instructions.
Block a conversation
- On your computer, open Google Messages for web.
- Next to the person you want to block, click More options
Block & report spam
OK.
Unblock a conversation
- On your computer, open Google Messages for web.
- On the conversation list, click More options
Spam & blocked.
- Find the contact in the list and select Unblock
Done.