Are you sure that you can't find a feedback link? I have had to hunt real good sometimes but as long as the listing was still up I can't recall not finding a place to leave feedback. I think I went through the sellers feedback left one time.
I will keep trying. Pored over it last night for the umpteenth time. When all else fails hand the laptop to my girlfriend. If it is there she will find it. Kind of like when you were a kid and you could not dfind something and your mom walks in the room and points right at it. :D
I was able to leave feedback on his feedback to me. Which does not let his future buyers see it but maybe it will spook him into replying to me ?