Many of us have become disillusioned and frustrated in the past with websites which appear to offer free products or services online but in fact do not. Some services are okay, a lot of them are poor, and only one has left me extremely satisfied.
The reason is because these numbers are not maintained publicly. Basically, with a reverse cell phone lookup, you can locate the address and name of the caller. This may explain why they find it difficult to understand that they can now use the internet, rather than searching through directories, to find telephone numbers.
You can use the zip or area code finder feature that some of these sites have. There can be times when cell numbers are included with reverse white pages, but that is rare. You can purchase plans for one year to lookup all sorts of information through these phone services online.
The Internet makes it possible to find people or phone numbers. Luckily, it isn't expensive, and provides you with options.