are we sure that this is his fault? i don't mean to say its your fault, but does he know he forgot to include it? if he doesn't know, and thinks YOU forgot, that could be real bad news for you. i had a similar case recently, i had the correct address but for some reason, the post returned it return to sender, forget the reason. i emailed the buyer and asked if he could split the shipping with me. after a while, i thought to myself...he's already paid for shipping, why should he have to pay again? its not his fault the stupid postal system returned it (not mine either, but its my job to get it to him)...i kept thinking what if i were the buyer, why should i have to pay again? so i emailed him back and told him i'd cover the shipping and send it out right away...
...its your choice of course, and yes, it probably is his fault, but it all boils down to your score over the shipping charge and whether or not its worth it to you...
ps...i have yet to get a positive from him (rolling eyes)
Kat