Before you place an order it will give you the estimated time + if there will be any delay.
But after your order, it will not stick to that original timeframe. So you can for instance order at 12 and it will say you will have to wait 30 minutes, but your order will be there an hour and fifteen minutes later, cold and not as tasty as it should be when hot.
The problem is they don't have enough drivers, so if you order something and the restaurant accepts it, they will start preparing it. While on the other hand, a free driver might appear an hour later to pick it up.
All in all, I wouldn't recommend ordering from here if you want to get your food fast. If you don't mind waiting and eating cold food, then bon appetit!