Many reasons exist for why someone may block his phone number from appearing on a caller ID. A number may be blocked because the caller is making a prank call and wants to protect his identity. The caller may want to protect his identity due to a divorce or domestic violence, or due to the sensitivity of his job, such as a social worker. There are now ways to unblock a private number and see who is calling.
Subscribe to a service, such as TrapCall. These services allow subscribers to see who is calling them, despite a blocked number.
Reject blocked calls to your voicemail. Calls to toll-free numbers legally can't be blocked. TrapCall sends your rejected calls to its toll-free number to unmask the blocked number.
Wait for your phone to ring again. Once the call runs through the TrapCall system, the call will return to your phone, displaying the caller's number. This process is seamless on the caller's end.
Answer the call or send it to voicemail. You can now answer the call by pressing the accept button on your phone. If it's a number you don't wish to answer, you can reject the call a second time to send it to your voicemail.
Phone users can accomplish this without the use of a service such as TrapCall by purchasing their own toll-free number.