As with any system that facilitates transactions between buyers and sellers, over time there will be disputes.
If you feel you are the victim of a non-sending seller, that is, you have bid on an auction, won, had contact from the seller, paid the seller, and after a reasonable amount of time you have not received your item, and the seller is not responding, then please contact our Customer Service department and we will attempt to assist you. Note that we cannot force any seller to do something, but we can investigate your claims. If the seller is found to be fraudulent, we will take action and will cooperate with authorities in any investigation.
Keep in mind that "life" has a way of interfering with transactions. In other words, most times a non-sending seller isn't trying to defraud you, rather, real-life circumstances have come up and have impeded the fulfillment process. Someone got sick. Someone died. Someone lost a job, or moved, or got injured, or their computer crashed and emails and/or contacts were lost. They access the internet via their mobile phone and their phone service is temporarily off. And so on. This doesn't excuse poor customer service on the part of the seller, especially after you have paid for the item or service, but it often explains what has happened.
We recommend trying several times via email to contact the seller. We recommend using our internal FetMail system, since it notifies sellers as soon as they log in that they have FetMail waiting for them. If after a reasonable amount of time you have not heard back, contact us and we'll see if we can assist. Again, we don't have any super powers, but we can, and will, investigate, and if contacted by legit authorities, we will provide contact information and/or supporting documentation to aid in any fraud investigation.