Flipkart — Delay in product resolution for refund

I ordered Samsung galaxy A 12 6 128 GB phone from Flipkart which delivered on 2 April 2022 . After delivery of the product I checked and find it that sound quality low.
mobile does not sound during a call is facing a problem like sound quality low. So I raised return request to flipkart for defective product.
From Flipkart, they arrenged technician & visited 3 times so far . He closed the issue saying network problem and other SIM can be operated.
In this mobile I need to install Airtel SIM which is not working .
This was not communicated while purchasing the mobile in your site.no information was given about the SIM in Flipkart site..
I don't want such mobile which can be operated other SIM .

They are ready to refund my money. I have been calling customer care service yet no proper response was given till date. Kindly take proper action and try to resolve my issue as soon as possible. They are forcing me adjust with that mobile to use with other sim. attached is the invoice notice and cancelled replacement

screenshot..

Thanks
Ravi Kumar gurjar