I've also learned from dealing with eBay to take time stamped photos of what I'm shipping right before packing and shipping.  If I'm buying something, I take pics of the opening process.  It recently saved me when I bought a used Cisco router from an Amazon seller and it turned out to be beat to hell and non-functioning.  He tried to claim that what I got wasn't what he shipped.  I had pics from the unopened box all the way thru the unboxing and pics of the serial and showing the damage when the box was opened.  Saved me $500