It's very naughty to charge like this. It seems like the hotel actually makes more money if you never turn up for your award reservation than if you do. Although in the T&C, you could give the hotel itself a call and you might get lucky. I suspect though that you might not have cancelled the stay at all, rather than cancelling it late? However late, it's still worth calling up to cancel bookings (I was able to cancel several bookings on the day, up to even 10pm!! without getting charged in the past). If you don't call at all, then of course they're going to charge fully according to the T&C, and this does not only apply to Hyatt.