TTK Prestige — Gas Stove issues and no response for complaints

I purchased gas stove from local market on 22/10/2020. From the first day, it was giving the yellow flame and blackening the utensils. Dealer asked me to change the gas pipe and I did. But no difference. Then I put complaint on customer care and techinician arrived after 15 days. But then again it was not working fine and gas flame is very slow. I open up new complaint on 17 Nov. but till now no response.