1. To block a call, from the Start screen, tap the AT&T Phone tile.
   
2. Touch and hold the desired number.
   
3. Tap block number....
   
4. Tap accept.
   
5. Tap ok.
   
6. To view blocked numbers, from the Start screen, swipe left.
   
7. Scroll to, then tap Settings.
   
8. Scroll to, then tap call+SMS filter.
   
9. Tap the Block calls+SMS switch to toggle blocking on or off.
   
10. Tap blocked numbers to view the list of blocked numbers.
    
11. To unblock a number, touch and hold the desired number.
    
12. Tap unblock.
    
13. The call blocking feature may not affect phone calls made or received via third-party apps installed on your device. Please contact third party app developers for assistance with such applications.