If you have in your possession a phone number but you don't know who it belongs to you can use a reverse cell phone directory to track down information on the owner. You have a telephone number but you want a name, what do you do?
However, when you have the number and not the name, the process is a bit different. Basically, with a reverse cell phone lookup, you can locate the address and name of the caller. It will take days before you can find the exact number and the corresponding address.
Why else do you think telemarketers, government officials, and collection agencies are able to find you, even if your phone number is unlisted. This is not as common as it once was, because this takes far more time than our modern means of communication. Mobile numbers on the other hand has to be collated manually and so it costs the services in order to provide such a service to us.
Don't be afraid to take advantage of what is out there. I hope you found useful and I wish you luck on your quest to find the best.