Nissan Motors — Vehicle break down

Address:

Mumbai City, Maharashtra, 400093

On 9th august i took my car from the showroom it broke down on 11august i took the car to the showroom and the concern person was karan he repair the car and gave me again i am getting. The same problem with the vehicle is have given it the showroom now they r blaming on me that bcoz of me starter isn't working they want replace and they r asking for money though my car is in warranty so what should i do hope u spk to the senior people and let me no as soon as possible with has to be done next