New e-commerce platform — Wish

Recently, I came across a new product called Wish. It is an e-commerce platform marketed as a marketplace for discounted items targeted towards customers who are not time-sensitive. Shipping takes over two weeks. It has been around since 2011 but has started getting attention since last year. Amazon has physical warehouses all over the world. But Wish does not have a physical presence in any form. How do they verify sellers? How do they make payment safe? How do they handle returns? Any thoughts?