Mother Dairy — store not taking back spoiled product. company not responding to complaint

This is a purchase made from capital hyper market, kavalbyrasandra, bangalore. Bill number 49992. Date: 27/11/2018.
I purchased 500ml nandini curd and it was a bit sour and also gave me a throat infection. Since this has happened with a previous purchase too, i wrote three emails to the email id listed on the packet: [protected]@gmail.com, but there was no response. The emails to them were dated: nov 27, 2018, 2:25 pm, nov 27, 2018, 7:29 pm and nov 28, 2018, 2:01 pm.

There are three problems here:
1. The company uses a gmail id instead of an official email id for addressing and tracking consumer complaints.
2. I took the packet back to the store but they did not accept it back or give a refund or replace it because i had already opened the packet. The same thing had happened a few years back at an official distributor of dairy products.
3. The company did not even ask me for the batch number of the product so that they could follow up and check if there were problems at the manufacturing stage or whether the distributors were not ensuring the product is refrigerated.

This a matter of consumer health. Please ensure the company responds to complaints and offers refunds for spoiled products.