If you have been unable to track down someone's cell phone number, it might be because the number is unlisted or blocked. In the past, this may have been a problem, but now there are online reverse phone directories that can find telephone numbers even if they are unlisted or blocked. These resources used to only be available to law enforcement agencies or bill collectors, but are currently available to anyone for a fee.
Go to BestPeopleSearch.com or iinfosearch.com. These sites are designed to help find people, allowing you to search by name, phone number, social security number or email address.
Click on “Hire a Professional” at BestPeopleSearch.com, and “Reverse Cell Phone Lookup Plus” in the complete directory section at iinfosearch.com. Best People Search costs $139.97 as of 2010, and iinfosearch costs $110. Both guarantee their results, which may include a name, address, account number or partial account information, date first reported (start date), possible alternate contact numbers and more. This service works on blocked and unlisted phone numbers.
Start your search by scrolling to the bottom of the screen and entering the phone number of the person for whom you are looking. You will be asked to "Create New Account." Once you do this, you will be allowed to save your current search as well as any other searches that you perform for 90 days. Pay the fee with a credit card or paypal. If you are a new customer you will usually get results within one to three days, and if you are an existing customer, you will likely get results faster. If your investigator is unable to come up with any information, then you will be refunded your money minus a $20 administration fee with BestPeopleSearch, while iinfosearch will give you a 100 percent refund if no information is found.