Mseller is right. if a vendor does all he can (usps delivery is totally out of the vendors hands) and you get a refund, the vendor did all that he could for the buyer. The vendor is out shipping, product and hell of a lot more time (packing it etc) than a buyer would. The other stuff that you mentioned is part of the game and risk. Hell, i lose a lot with the btc fluctuation on every transaction. If a vendor does all that he/she can then I would give them a 5 (if i were a buyer) and every buyer that is also a vendor would surely agree..