From the Start screen, tap the Phone tile. 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.
Tap the History tab.
Tap the Menu icon.
Tap Blocked calls.
Tap the Menu icon in the top left corner.
Tap Block list.
Tap the Add icon to add a number or contact to block.
Enter the number you want to block.
To remove a number from the block list, tap and hold the Desired number.