Treasure Haul Online — Mobile phone is not detecting the SIM Card

I have purchased the Motorola G60 phone via Flipkart from this particular seller. I received this product on July 27, 2022. When I switch on the phone, this device freezes/hangs during their first time operation. The front camera of this phone also captures the blurred image. Also, while I heard the phone the sound is not clear. So, I decided to replace/return this phone. I called customer care they said we can't refund it we can only exchange it that too if the technician approves it. During the visit of the technician, they rejected the request for a replacement. When I am again raising the return request, the seller, again and again, rejected the request. After, placing so many humbly request I make a call to Flipkart customer care they said that the seller does replace the device. I have purchased the phone from my 12 monthly savings, but choosing the phone from this seller is not worthful. They do not value the investment of people who believes in them and purchased the phone from them via Flipkart. Now, another problem exist in the phone, they are not able to detect the SIM card. Whenever someone call me either they show that the dialed number is busy with other call or the it is switch off. What, can i do with this phone. No one is giving me the solution.