Take a look at Chinese e-commerce sites and learn how they deal with frauds, they have been dealing with these for more than 10 years. In terms of technology,

Take a look at Chinese e-commerce sites and learn how they deal with frauds, they have been dealing with these for more than 10 years. In terms of technology, one can use machine learning for fraud detection. In terms of business operation, they have dedicated e-commerce site for official sellers, and there are several sites aiming up middle class market where products are curated and QCed by the sites.(sort of higher end Amazon Basics)