Faber 3 burner cooktop service and replacement issue

Dear Sir/Madam
I had purchased 1 unit of 3 burner cooktop of Franky Faber India Limited from Asian Appliances, Address- 91/39D/1, Bose Pukur Road, Kolkata- 700042 Phone- 033- 24420127, 033-24424985 and the sales man was Dilip Nandy, in the month of April’13. In the month of May’13, one of the knob of the burner came out, while cooking, we had to immediately switch off the gas knob, so that it doesn’t couse any accident.I quickly called up the customer care, Even though I kept on requesting for early service the customer care said that it will take 48 hours for any executive to visit my house. I had to take the help of some local small time gas stove fellow to fix the problem and the Faber fellow had called me up after 48 hours find out what is the problem and weather he needs to come or not. That time I wondered that while I was scared of Gas Leakage and I didn’t had any other option to cook food, still it took 48 hours for Faber to respond. I definitely didn’t expected this kind service.
Again after 25 days, the middle Gas burner knob came out along with the spring and the metal. This time it was very serious as I could smell the leakage of cooking gas. The entire house was smelling with the Gas. I turned off the burner of the gas and called up the customer care. Again it was like pre recorded “48 hours”, and after 48 hrs the guy of Faber calls me up to find out if everything is OK. That time I got very annoyed with the casual approach and big shot feel of the guy of Faber. This time I some how managed myself to fix the issue.
Again after 30 days the problem propped up. Just to mention few of the complaint numbers- 1308705542, 140506964405, 1305632024 and there are few more which I have not recorder. This has happened for at least 15 times from the date of purchase, which is around 1 year. Again today the middle knob along with spring and metal, was out of the stove.
From last complaint , complain number 140506964405,on 07/05/2014, I am requesting Faber India limited to replace my cook top as any day due to gas leakage from the stove, it can catch fire and lead to accident and unfortunate situations, but I haven’t got any possitive response from them. As I am facing problem from the very next month of purchase, so I want a replacement of the cooktop or a money back for the same.
Please help me.
My details are-
Indrajit Bhattacharya
C3, 859-Gangotri Apartment
Purbachal Main Road
Near Shakti Sangha Club
Kolkata-700078
Mobile- 8420052231