We ordered some stuff from (at least theoretically) a reputable company. We had to pay about 2 months ago, but kept getting emails telling us that the stock hadn't arrived yet and to just be patient. Then a couple of weeks ago, they told us that they actualy didn't have the stock and that we'd have to get a refund. But they were refusing to respond to any of our requests for the refund, so we contacted Paypal and they told us that we'd missed out on the 45 day window and they couldn't help us.
The company we ordered from eventually (after over a week of chasing) paid up, but if they hadn't we would have been left high and dry by Paypal.