Hero Motocorp - Vehicle damaged by service provider

I have done my vehicle service at the authorized hero service centre on June **, ****, and was delivered on the same day at * pm. As of today on June **, ****, I was cleaning my bike I saw there was damage in my vehicle, where the side cover of the bike was seen broken. I informed the same thing to the supervisor who attended the vehicle but he said he can't do anything like the service was done * days ago and the vehicle was in good condition. When I gave it for the service to be done I have paid INR ****/- for the sake of free service extension. If this the case they damage the vehicle and handover to the customer I want the amount to pay back for the free service extension and claim for the damages and time I spent on the issue. Kindly do the needful.