Premium collected but coverage is less than agreed with dealer

I am a resident from Hyderabad and Purchased a new vehicle (car) Datsun Redi go from the Dealer ( Lakshmi Nissan ) – Nagole, Hyderabad on 6th July,2016 . At the time of car delivery, Dealer promised me that , they will provide me Bumper to bumper insurance and collected 14,512/- from me and opted insurance for my new vehicle from new India Assurance. After , 11 months , I received car insurance documents from the dealer via email and I realized that , its normal insurance copy and my car won’t covers nil dip/ bumper to bumper insurance as promised. I really upset and wrote email to them with all proofs , they replied me saying that, they have opted a normal insurance to your car ( as per price list) and at the time of car delivery, I have singed the delivery summary sheet( in this sheet is just mentioned as comprehensive insurance) . Dealer price list never say it will normal or nil dip insurance ( I have a copy for the same) I was trying to explain dealer that ,sales