How can I block a Messenger contact?
You can block a Messenger contact to prevent them from calling and instant messaging you, and from seeing your status.
To block a Messenger contact:
Sign in to your Microsoft account to manage your contacts in People.
In People, select Manage at the top of the page, then select Limit access from the drop-down menu.
In the box Name of Messenger friends, enter the name of your Messenger buddy you want to block and select it.
Select Limit access. The contact’s name will appear in the box under Limited access, and you’ll see the message “Your changes have been saved” to confirm that you’ve just successfully blocked a Messenger contact.
Important: Your name will still appear in the Messenger contact’s list until they remove you.
If the Messenger contact you’ve just blocked is also your Skype contact, you’ll need to block them in Skype as well.
To unblock a Messenger contact:
You’ll find the Messenger contacts you’ve blocked in People in the box under Limited access. Choose the contact you want to unblock, then select the Grant access button. The message “Your changes have been saved” will be displayed.