If you're still having trouble, some phones allow you to reset the call block settings to their default state:

: For most Panasonic models, you can jump directly to the block list by typing [#] [2] [1] [7] on the numeric keypad.

Handset - unblock a single number or a range of numbers * Press [ CALLBLOCK ]. * Press the arrow up ▲ or down ▼ button to select "