How to Retrieve a Blocked Number on a Cell Phone
It can be frustrating to see "Blocked" on your cell phone caller ID. If it's an incoming call, you may not want to answer the phone without knowing who's calling. If it displays on your "missed calls" list, you don't know who to call back. But just because a person has a blocked caller ID doesn't mean it stays blocked. There are techniques and tools you can use to retrieve that number.
Press the "Redial" button on your cell phone. If the blocked call was the last incoming call on your phone, press "Redial" to call the number back. If you get the person's message recording, he might provide his number on it. If you don't have a "Redial" button on your cell phone, check your product documentation or call your cell phone provider to check if another key sequence functions as a redial (your cell phone provider support number is on any of your statements).
Request Anonymous Call Rejection. With this service, when a person with a blocked number calls you, the caller hears an announcement that you do not accept blocked calls, and that the call will not go through unless the caller unblocks the number. Contact your cell phone provider to inquire if they offer this service (which typically is available for a monthly charge).
Purchase an unblocking service. Use a product such as Trapcall, which unblocks Blocked and Restricted calls. Trapcall unmasks incoming blocked calls and displays the caller's number on your cell phone caller ID. Trapcall offers different pay-as-you go plans (caller ID unmasking, voicemail transcriptions and more) you can sign up for at its website (Trapcall.com).
Trace the call. If you're receiving harrassing phone calls from a blocked caller ID, contact your cell phone provider and ask if they provide a code, such as *57, that you press after receiving a harassing yet blocked call. This service is internal to the carrier, who traces the harasser's name and phone number but does not provide this information to you. Your cell phone provider will request you sign an authorization form, after which they'll forward the harasser's identity to local law enforcement. There is a charge each time you use a call trace code.