Flights booked to Punta Arenas

I just booked the flights from Santiago to Punta Arenas and back. Helpfully, your saved trips on expedia.co.uk don't appear to be properly dynamic. They do show price changes, but I was just allowed to go right through the booking process for my saved trip (credit card details entered, the lot) and then it told me the Santiago-Punta Arenas flight was no longer available.

I assume it's full. Maybe if I'd booked yesterday it would have been OK, but then I can't possibly know that, since the saved itinerary didn't show the problem today. It's not the end of the world, I've just picked a different flight on the same day. Most of the flights are at stupid times like 2:30am. The flight I wanted left Santiago about midday and got to Punta Arenas about 4-5pm. As it is, I've had to settle for one leaving Santiago at about 5pm and getting there about 9pm, which is a bit crap but not the end of the world. I fly down there next Tuesday and back two weeks later.