This document provides four options for unblocking or finding out blocked phone numbers: 1) Dialing *69 to call back the last number but not reveal the caller's number. 2) Dialing *57 but it only works locally. 3) Calling your phone company to track the number with explanation. 4) Using a caller ID unblocking service like www.kosspa.com/ubc which can fully unblock any blocked number and sometimes provide the caller's name and address.