1st I got an item from a fraudulent 3rd party shipper. Did not get my money back and amazon claimed they don't know his identity
2nd Packet got stolen. Amazon claimed based on statistical analysis this packet is assumed to have reached me. Delivered to "mailbox". Paid with CC, made a charge back, closed my account.
You know what is a pretty good competitor? eBay. As a business it may be terrible, but as a market place it is quite good.