Swiggy — Partial and used item received

Have ordered buy 1 get 1 pizza from 'oven story pizza -standout toppings ' via SWIGGY.Order I'd is :[protected] for RS.603 Rs.
When ordering, the information was the food would be delivered at 8.37 pm.
It reached at 9.00 PM before delivering the product only delivery boy sent a order delivered message .
When I opened a box I saw only 1 item and second item is missing (but 1 get 1) and box is so cold .
When I called customer care they said 'sorry for the inconvenience we will give 115 rs coupon' i denied and customer executive not solved and asked them to transfer the call to his supervisor, in the mean time I got a dout on the order delivered hence I opened a pizza box and checked and found that 1 slice is missing I was waited for 30 mins to get connected to supervisor since call not connected and not recived any update from customer care executive .I disconnected and called again and one representative picked the call and I have given all info and sent all photos still he said he can give only 115 discount coupon .
I am very disappointed with the service I lost money and lost item .
Kindly need help on the same ..