@Bonsu, while I agree email verification is a must for entirely technical reasons, am strongly against to further verifications. Privacy is a huge concern for too many people all around the World. You can find only a few persons who don't mind verification requirements of online companies. Additionally, if the buyer doesn't pay it's not a problem. As a solution marketplace should set a time limit for payment like 1-7 days. That's it. It's not the end of World if a buyer wastes my 1-7 days. It's the nature of all online purchases. Further verifications can't help anyone. If you have all the details of the buyer, can you sue a person on the another continent for not paying in time? It would need too much time and money even if the buyer is in the same country. What will you do if buyer provides valid reasons for not paying in time? Nothing. It's not worth. You can't know why a buyer doesn't pay in time. The best solution for your problem would be to set BIN only and preventing ability of making offers, at least for the domains on marketplaces. Verifications don't help anyone, will only keep many potential buyers away from such marketplaces.