Flipkart - Flipkart delivered defective product no refund after acceptance

I had purchased a (Refurbished) OnePlus * (Midnight Black, *** GB) (* GB RAM) on *st April, ****. Delivered on *rd April,****. from Flipkart.

Issues - *. The phone, as soon as I launched a game, after **-** seconds shut done (Dead, battery was **%), just immediately died.
Issue - *. Phone does not charge after **%. It just stops charging even when the charger is plugged in. Also, the charger is making a noise as if some component is loose inside it.

Case : I bought the phone variant */*** midnight black from Flipkart, seller was VONIX INDIA.
The phone arrived on **, April ****, and on the *rd day of use (*th April, ****) I encountered this issue - The phone, as soon as i launched a game, after **-** seconds shut done (Dead, battery was at **%), just immediately died like when you are using a computer and there is electricity cut in the area and the computer drops dead shut.
I thought it was an issue with the app so I stopped using that app. But then I was using the file manager app to copy * photos of *.** mb total to a different folder, Same thing happened the phone dropped dead.
After that the same error happened in Clash of Clans, Files by Google, Instagram, Snapchat, Camera App, BGMI. Initially it happened in Genshin Impact and The Legend of Neverland.
The phone was not even heating, the Flipkart executive suggested that it might be due to heating.

After encountering this issue I sought Flipkart executive customer care team help. They told me to update to latest software, reset the phone app and finally reset everything. Nothing Worked.

Finally, on **th April, **** I filed for return. NOTE THAT I WAS WELL WITHIN THE RETURN POLICY PERIOD. I received another mail that my return was accepted on **th April, **** and text message that the person was out to pickup the phone. Later on the same day without any email or message or any kind of indicator or acknowledgement to me, my return was cancelled. I found out later when I went to Flipkart site and checked the status of my order.

I called help support and again I got the same mail return accepted and text message out for pickup on **th April, **** and same refund cancelled *nd time same day.

Reason both the time was stated as return policy expired on Sunday. Where as I had filed for return on Sunday that is within the return/replacement time period.

Again third time I called help support on **th April, **** and again I got the same mail, return accepted on **th April, **** (** DAYS LATER) and a technicians visit was arranged. The technician visited on **th April, **** and checked the phone and accepted that the phone was faulty (conformation via text message was received). Refund Request accepted on **th April, **** (mail).

Then, the pickup text message was received "Out for pickup" on *nd May, ****. Then on same day pickup unsuccessful.
Then again Pickup text on *th May, **** and unsuccessful on same day.
Then *rd time Pickup text on *th May, **** and NO PICKUP DONE, OR NO ONE CALLED FOR PICKUP, Then finally this message was received "Pickup Rejected (product mis-matched): Pickup of (Refurbished) OnePlus with tracking ID FMPRO********* from flipkart.com has been rejected. Contact flipkart.com CS for further assistance. Click to give feedback: http://ekrt.in/*gukyJNNNN"

I have suffered a great deal of Mental Harassment from Flipkart. No one is taking responsibility. I am a student and had earned this money via my internships which paid only ****-**** per month. I have an immense requirement of a smart device and had bought this due to my old phone been stolen. I have suffered financially as client dealing have been very hard, the phone would now die even when I don't use it due to heat caused by the summer heat. It wouldn't turn on unless kept in-front of a cooler for at-least * minutes. I have lost many internship offers to further upon my career, important updates from my college, Interviews, etc., all due to not having a basic phone.

I called help support again on *th May, **** and they said that no reason is listed and refund has been cancelled and kindly wait till **th May, ****.

Flipkart refused to take responsibility even when it is guaranteed by them. They will go against their own policy and refuse to take responsibility. The policy clearly states that only one replacement for mobiles will be provided but in case seller is unable to provide replacement then refund will be provided. I was only given the option of refund when I had initially filed for return on **th April, ****.