There are several ways to identify a Coach bag on eBay including the YKK zipper, authenticity tag containing a style number and a unique serial number, straight stitching and the pattern on the bag are always centered. Sloppy workmanship on a bag is an immediate sign that something is not a real product and will be visible in pictures.
As of 2015, Coach operates an eBay page that is run directly by the company. The best way to guarantee that a customer is getting a real Coach bag is by purchasing items through this page. It is possible that some owners of Coach products will resell them through eBay, but they will have all the same indicators of a true bag.
If the seller asks for abnormal information or requests additional information outside of the payment information submitted directly through the eBay site, these products are likely not authentic. If a customer purchases an item from eBay and does not receive it as agreed, it is important that it is reported right away for tracking. If the company or seller is unable or unwilling to track the Coach bag, reporting the seller and requesting a full refund is the best option.