Facebook is used by cybercriminals to sell and buy creditcards which have been stolen from malware victims. There are many ways to fight these cybercriminals, one of the fastest way is to use the report function provided by Facebook. The problem which comes forward is the fact that Facebook does not use the reports that are filled by Facebook users.
A lot of creditcard markets can be found on the darknet. But some choose to sell the stolen information on Facebook.
Take a look at the following picture which was provided by a security researcher.