1. From the home screen, tap the Messages icon.
   
2. Tap and hold the conversation with the contact you desire to block.
   
3. Tap Register spam number.
   
4. Tap Yes.
   
5. To unblock a number, tap the Menu icon.
   
6. Tap Spam manager.
   
7. Tap Spam settings.
   
8. Tap Spam numbers.
   
9. Touch and hold the desired number.
   
10. Tap Delete.
    
11. Tap Yes.