1. To block a number, from the Start screen, tap the Messaging tile.
   
2. Tap and hold the message thread you want to block, then tap Block contact. 
   
3. Tap Block.
   
4. To view a list of blocked numbers, from the messaging threads, tap the menu icon. Then tap Block messages. 
   
5. Tap Block list.
   
6. Your blocked numbers list will be displayed.
   
7. To unblock a number, tap and hold the desired number. Then tap unblock number 
   
8. The number is now unblocked.