[Resolved]  Hindware — Service not provided

Hi All,
I bought a 3 burner gas hob of hindware about 7-8 months back. Right from the begining there were problems in the product the burners used to get extinguished without any reason at all. That meant that if I am not looking at the gas and it gets off the gas keeps on leaking which all o[censored]s know can lead to something very drastic. The engineers which came only after lots of shouting on the phone and that too at thier own convinient timings said nothing was wrong with the product and that I should keep my kitchen windows closed. So only afer 3 months of pestering and threatning of legal action did they obliged me by replacing the product.
Now in the new stove provided the knob of one of the burners was broken which I was assured will be replaced the very next day. That was the day and 5 months have gone by I have not been able to get the knob making my three burner hob a two burner gas for me. I have lodged complaints and complaints with their customer service cell only to get a call from them after every 20 days or so asking if the product is ok now without any of their engineers coming over at my place.
Please advise what can I do in this case???