I bid on an item off a US seller with >50k feedbacks. After I won the auction and paid the item, the seller sent a cancel transaction request and refunded me through Paypal, saying he ran out of stock. Obviously I cannot make an out-of-stock item become in-stock, so I will probably accept to cancel the transaction (or should I decline it?), but what feedback should I give? I have never left anything but positive feedbacks, and don't want to leave a neutral or negative if they don't deserve it.
