TVS Sundaram Honda - Damage my car during service centre

I gave my car (HONDA AMAZE) for service on **.*.** at TVS Sundaram Motors @SALEM. On the next day that is on **.*.** at *.** pm, they informed me to come and take back the car after completing the service. I reached by *.** pm and I was delayed due to heavy rain and storm. My car which was in the showroom met with an accident in that rain. The roof and the bonnet were damaged. But they said the car is not their responsibility it is fully at owners risk. They sent an email attached with the job card an additional page after my signature that if any natural disasters it is owners responsible. I have attached that mail also. Finally, after * days with lots of conversation, they repaired the damaged car and returned to me on **.*.**. It is really a very hopeless experience by me.