If you want to be able to buy credit-card numbers from the dark web, then there are two methods that you can use to get your hands on this type of information. The first method is to visit a site such as a free reverse lookup or search engine such as Google and enter the phone number you wish to investigate into the search box. If you were lucky, you might get some useful information such as a name and address. Although this method will still leave you without the information you need, at least you will know the person who owns the phone number you are investigating!