I always assume no feedback is good feedback. I figure if they're NOT happy (for whatever reason) they'll be quick to get in touch. I sold an item once (very carefully packed and labelled) that had various parts to it, the buyer got in touch within minutes of the item arriving (I would imagine) to say there were pieces missing. I replied quickly to say no, everything was there, the boxes in the main box are all clearly labelled, please look again. Fortunately the buyer got back to me straight away with apologies to say everything was there and they'd unpacked it in such a rush they hadn't spotted all the boxes. I know she received it and was happy because of this email string, but she didn't leave me feedback on ebay itself.