Bridgestone Tyres India — Car Tyre got burst while travelling.

I have purchased car in September month(7565 KM). Its only 8-9 month and Tyre is in still warranty period. I was travelling with my family on 27th April, suddenly rear right Tyre got burst suddenly We were fortunate enough that no accident happens at that time. But all the conditions were normal i.e Tyre pressure was normal and speed was also 70-80(Highway). I have filled that claim regarding this but company replied me that it occurred due to sharp object. But my concern is that no one has checked/inspected the Tyre physically they have came to conclude by seeing only photos of the Tyre.
I am pretty sure that no sharp object has touched the Tyre it has happed due to defect in Tyre.

Please help me in getting resolution on this.
As I was travelling with my family sudden Tyre burst would have lead to very serious accident.