It is 30 min or free this is what they advertise, but yesterday we ordered and it got delivered 20 min late, so I asked the delivery boy about the free thing, but he said the conditions apply and he could give only 300 discount, I accepted it.
My view is even for other hotels who all are providing home delivery will never ever reduce a penny in the bill, if the delivery is late. For a bill of Rs.1000.00 I paid only Rs.700.00 so I was happy.