Hero Motocorp — engine problem

Address:

L12B GALI NUM.42 SADATPUR EXT, 110094

Dear sir,
I was purchase a bike (Passion expro 110cc). Total time 3 years, total kilo metres 33000. This is current data. But my bike engine fail before 3 months.
When i had gone to hero service center he told me your bike ring piston damaged. He give me projection approx 8500. But hero motocorp give 5 years engine guarantee. My friend also use same bike model and he is facing same problem. So please solve this problem.

Thanks
Sunil kumar