I understand that sometimes vendors keep tracking information so that this can be provided as proof that an item was shipped. But what if they do not? How do administrators of these marketplaces help come up with a resolution when it is one person's word against the others? What kind of resolutions are typically seen?
If you have not finalized early, there's a system through escrow where you can request a refund from the vendor; although a lot of vendors don't offer this, and some only offer a 50% refund