Flipkart - Flipkart did not replace damaged product and cancelled return requested on the very next day of deli

I had ordered Crompton ** L cooler from Flipkart on **th May **** which was delivered on *th May ****. As the air vents slits of the cooler was not working as expected we requested to return it on *th June **** and Flipkart agreed to pick up the faulty cooler by **th June **** and deliver replacement by *th July ****.Inspite of multiple follow ups the order was never picked up and never replaced.I was assured to have it resolved by *st July **** but Flipkart cheated again and did not resolve the issue.Each time I opened a follow up incident ticket, they resolved it like cheaters without actually providing resolution. To my utter surprise, they cancelled the return on their own without informing me on *th July ****.What should I do with that faulty product? My hard earned money has been looted by Flipkart in lieu of faulty product which was packaged and delivered. On top of it, it has caused *s mental trauma and harassment and waste of efforts and time.
I would like to have full refund along with extra compensation for waste of time, efforts and money and mental harassment. I want to sue the Flipkart in the consumer court in Patna and send them the legal notice. Please help.