1. From the Start screen, select the Phone tile.
   
2. Select the Menu icon, then select Blocked calls.
   
3. To block a number, select the Menu icon.
   Note: 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.
   
4. Select Block list.
   
5. Select the Plus icon.
   
6. Enter the desired number then select Block.
   
7. To unblock, touch and hold the Desired number and select Unblock number.