I Want To Resolve My After-sales Issues With Volkswagen Polo. Whom Do I Contact?

I purchased a Volkswagen Polo from a dealer in Thane(Mumbai,India) couple of months back, with registration number MH04-FA-0736. Since beginning, I have very bad experience with your dealer. In spite of specifying the color, they registered the vehicle with different color. Since the vehicle was registered at the time of taking delivery, we reluctantly accepted the vehicle. A regret letter from the dealer is available with us. After taking the delivery, we found that the rear door was not locking which we solved ourselves reading the instruction manual and was informed to the dealer. This means the vehicles are not thoroughly checked before delivery. Within a month’s time, the front grill of the AC has gone inside while adjusting the flow direction (without any excessive force). Now the dealer is not ready to fix the problem of the AC grill though the vehicle is just 3 months old. I am very disappointed with the service provided by your dealer and in turn the world known VW brand. I already have a Honda car and never faced any technical as well as service issues and thought VW is equally known and shall provide proper service. But your dealers are tarnishing the image of VW. Can you look into this quickly please? The photos of the grill are attached for better understanding. Additional to this the airconditioner stops working suddenly. I tried to fix this from the dealer, but is recurring again and again. Is there any way the complaints can be addressed seriously?