I won an auction on trademe, being sold by a professional dealer, paid via credit card and expected to pick it up later in the week. A few days later they emailed me to say that they no longer had the item, and it had been misplaced, and either they would refund, or I could choose a different product to buy with the amount I had paid. I emailed them back asking if they could source me one from somewhere else...no reply for a week...so I followed it up again, and they replied to say they couldn't.  Can they do this? I thought that an auction was a legally binding contract, and neither party can get out of the auction, so they have to source the product from somewhere in order to fulfill the auction contract? I know that if you win an auction and you want to pull out, you can't and the seller can take you to court to retrieve the money.
What is more annoying is that they had a number of the items and I was outbid on all of them over a few weeks, but this was the final one, and  eventually won it. I suspect that another one of the items they had sold to someone else was faulty, and they used mine as a replacement. If it was a private seller, I would probably just get the refund and be done with it. But I think professional traders should know better. I could buy from elsewhere but would be paying more than double what I paid.