[Resolved]  Cars24 Services — Fraud warranty

I purchased a Honda City from cars24 and at the time of delivery there was an engine light. I asked a guy why is the engine light is blinking and he said
" Sir you scan this car and engine light will be despaired" then I took the delivery in August. next month when I sent my car on service my mechanic said there was a problem with the oxygen sensor but I activated it. whenever you cross 120kmh then only you will get to know about it that oxygen sensor is working or not. So when I crossed 120kmph after couple of days I found that engine light is blinking again. My mechanic said we need to change the Oxygen sensor I said I am having a warranty of 6 months I'll speak to the cars24. on December 28th cars24 has picked up my car and till 3rd of January I was calling them every day to check when I will get my car back. Now today they are saying Catalytic Converter is the problem and that is not covered under the warranty. The cost of the catalytic converter is 30k. Again like I said when I picked my car there was a engine light blinking and the guy who gave me the car he also know about it and I called him today and he agreed that there was a problem on first day. So here is a question, Do cars24 really check the car before they deliver it to the customer?. I don't want to know that oxygen sensor is the problem or catalytic converter is the problem I need my car fixed and deliver asap because the problem was from the day one and I inform the same guy and I have a proof on it.