A restricted number is a phone number that shows up as “Private," “Restricted,” or “Unknown” on the Caller ID display of a phone. This sometimes happened when a business calls your phone line. It happens frequently with telemarketers who are trying to call anonymously in hopes that you will answer the phone. Identifying “Restricted" numbers does take some trial and error effort, but there are ways to identify the caller.
Keep track of the pattern of the restricted phone number. Keep a journal of what time the call comes in every day using your phone bill. This could give you an idea of who it may be if you know someone who fits the time frame that the calls are made. The phone number is sometimes listed on the phone bill.
Contact your phone company and ask what the process is to identify “Restricted” phone numbers. Give the phone company any documentation that is requested, such as the journal that you have kept for the pattern of phone calls.
Contact your local police to see how they can help you. The authorities are familiar with dealing with this kind of issue if the calls are excessive. Excessive, unwanted phone calls may be considered illegal harassment.