Domino's Pizza — Free delivery refused

I am Ritaban Sasmal of Garia, Kolkata700084 ordered 4 pizzas from domino's.As per my knowledge I was supposed to get all the pizzas at free of cost if the pizzas get delivered after 30 minutes.The pizzas came to me after 1 hour.When I took the pizzas, the delivery boy told me that there is no such policy...he also told that if the delivery is after 30 minutes then there is a discount of Rs. 300/- Though I didn't take the order but he was not supposed to do so.My order no. was 126.