Disappointing experience with Woolworths online

I placed a grocery/food delivery online two days ago to be delivered today (Saturday, 16 April) as this was the soonest available delivery slot. My order was processed and this morning at 6:30am Woolworths online called to say the item I ordered is no longer available and my order is being cancelled. First of all, calling your customers at 6:30am on a Saturday morning is absolutely ridiculous! Secondly, why am I only being notified the day of delivery that my item is no longer available? Surely this would have been realized when the order was placed and processed but could not be fulfilled? I have had other problems with Woolworths online before but this was the most disappointing as I now am not able to look for an alternative product elsewhere in time.