Big Bazaar — overcharge of delivery charges

Address: BB ATLANTIS MALL CIVIL LINES ALLAHABAD

Website: shop.bigbazar.com

I made an order of rs 4418 including delivery charges of rs.150 on 08/04/20 of groceries on big bazaar. While packing of the items some out of stock items were removed and the order amount reduced to rs.2813 including delivery charges of rs.150.
The delivery charges increases with the order amount. For order amount less than rs.3000 they charge delivery charge of rs.75.
My order amount reduced after packing of the product but the delivery charges did not reduce.
I complained several times to big bazaar but i did not get any refund of the excess delivery charges that i was charged.
Order no.[protected]
Order date - 08/04/2020
Delivery date - 10/04/2020
Order name - anuradha singh
Payment mode - credit card
Order to - bb atlantis mall civil lines allahabad