Dont do anything by urself , the car is in warranty , just bang into them and tell them u want to get it fixed under warranty or a new car. If they show any notions simply lock the car and leave it there at thr place telling them that they ll recieve a legal notice from your attorney.
Dabna nahi warna ye kaam hone wala nahi, its ur right u have paid a damn huge amount of money so ur stance should be aggressive rather defensive.
hope this prob resolved soon.