Try to look at it from a buyer's point of view. I bought 3 chips from the same seller, I received a torn empty envelope. The seller would not cooperate as far as providing information for a claim form for the post office, he certainly didn't offer to replace any chips (nor did he offer insurance). I left him negative feedback. He left retaliatory negatives for me, even though he had the money. Was it fair that the seller could leave me 3 negatives, even though I'd fulfilled my part of the transaction and he had the money??

I agree with Robert & Victor. Upon receiving payment, the seller should leave positive feedback. If further issues develop, you can respond to the feedback comment that was left for you.