Sansui — TV Remote not working

LT Nano TV 55 inches was bought on 30th November 2020, which means that it is under warranty. On 6th November a complaint was lodged that battery is showing low even after changing cell in the remote. Technician came n said to change cell from Everyday to duracell. He told us to use duracell braNd only.
We did as he said. But now it's not working again. I lodged a complaint again yesterday. Today on phone technician is telling that I have to change the remote, which is chargeable.
Why remote is chargeable when tv is under warranty
Whether the quality of remote is so bad that it got spoilt even before one year.
I would like to emphasise here that remote was being handled very smoothly, as no small children or pets are there at home