As an old git, to who all this feedback malarkey is a recent, eBay inspired thing, I'd say that it isn't one's right, having sold something, to expect or demand feedback, praise, or whatever. If you offer an item for sale and someone buys it and doesn't ask for their money back, that' the end of it. You have no right to a pat on the back. If you get one, it's a bonus. You have taken their money, after all. It isn't as if you gave them a present.
The same applies if you buy from someone. You pay them for an item they own. It's a fair exchange. Praise and stroking isn't part of the deal.