Some companies and individuals choose to make their number unavailable to others. Some want to protect their identities. Others -- like collection agencies -- don't want people to know who is calling for fear they won't pick up. Anyone can temporarily block numbers by pressing *67 on their phone prior to dialling. However, some people refuse to answer a call that comes through from an unavailable number. Some of these calls are telemarketing or harassing phone calls, while others may be people who only want to protect their identities. There are ways to find out who is calling even if the number is blocked.
Search for the phone number if the number appears on your caller ID. Use search engines, such as Google and Yahoo. In some cases, the phone number may be listed somewhere. Some websites also compile lists of companies and the phone numbers they use. This method is not very efficient as an unavailable number is generally not listed.
Call your local phone company if you believe the calls are harassing. They can put a trace on your line to find out who is calling you from an unavailable number. A call "trap" requires you to provide your phone company with the date and time of the calls so it can trace them. This service is generally free. For a fee, you can put call traces on your line, which allows you to hit *57 to find out the number of the caller.
Request a privacy manager add-on for your phone line. Privacy manager requires all callers from unavailable numbers to identify themselves before the call rings through to you. If the caller refuses to give the information, the call never reaches your home.
Ask your phone company to provide you with a list of incoming calls. In many cases, phone companies keep detailed lists of incoming and outgoing calls for a limited amount of time. This list should provide you with any unavailable numbers that called your phone line.
If any harassing calls threaten you or your family, contact the police immediately. While your phone company may be able to provide you with the number, it cannot protect you.