Flipkart — Flipkart exchange offer scam on mobile phones

Thad ordered Google pixel 6a that costs R$
29, 999 over Flipkart and I had ordered it only because it had a exchange offer for old phone (realme 5i) for Rs 4800. Once the delivery agent came he checked the phone and said that Flipkart rejected your old phone and didnt mention any reason for this and persuaded me to pay additional 4800 rs for the old phone value. Then he told we can raise customer complaint.
When I raised the complaint the even after talking to many customer service executives not even single person showed any concern and they keep on closing the ticket without resolution. When asked they say we have provided resolution. This has been happening from last 15 days and it is mentally stressful and harassing. I realised this is a total scam by Flipkart for selling mobiles in favour of exchange offer and in return they don't accept the old phones and not even mention why they have rejected.
Order ID: OD[protected]
Order Date:[protected]