Swiggy — domino's decorating services

Address:

Shop no. 6-7, commercial shopping complex , Shanti niketan , south delhi, New Delhi, New Delhi, Delhi

I ordered pizza from domino's by applying swiggy40 discoust. After discount it costed me rs 140. When i went to take the parcel from the delivery man, the bill showed there was no discount. And it costed rs 227. I checked my order details, it changed, and showed no discount was applied. This is absolutely ridiculous that after giving a discount, you are showing no discount, and we have to pay more money.
As a student we can't pay full money and this time i feel really deceitful by your side.
I want stringent methods to be taken for this. It would be appreciable if you refund my money.