Soldato
You can always let him know that if you don't receive all of them back, you will simply have to block the "lost" ones' IMEI and he won't be able to use them anyway.
This thread reminds me that ebay is not worth when selling certain items. I still use it when buying/selling games etc and never had any issues and I've got over 240 positive feedbacks now.
although I'd expect the seller to turn up at my house with a load of big mates 
maybe i was wrong, maybe because when i spoke to ebay i said i did not want my address given to the person, i duno, but they did not ever return it and i had my money restored
ok a little up date
ebay asked the buyer to post the item back and submit tracking information by the 24th of september. the buyer hasnt but the case is still open. what shall i do now?
Really annoys me stories like this
ebay in principal is great but there are so many people out there playing the system and know how to do it!
It puts so much pressure on the sellers now to basically prove your innocence.