what do i do if unblocking doesn’t work

To unblock a number, go into your contacts, scroll all the way down, and any contacts you’ve blocked with the app are listed as zzBlocked_.. ..delete the one you want to unblock.

If that doesn’t work, it means that you have another copy of the contact blocked independent of Reverse Lookup. Also, press your phones menu buttons, and then “contacts to show”, and make sure you are viewing all contacts. The wording may be slightly different depending on your device.