Hero Motocorp — Dump product with worst service

Hi hero team,
I have bought a hero duet scooter in 19 march 2018 form jai sai motors, and today (06-june-2020) i had been handover the scooter for normal service in same service center in morning and they have checked my scooter and told the estimated cost of 1100 but after 5 hours, service center executive called me and told, some parts has been damaged in your engine so need to replace some parts and shared the estimated quotation 6772 rupees.
How it is possible that engine has been damaged within 2 years after purchase the scooter. Is it worst parts in the hero duet scooter?
And what the benefit of 5 years warranty, when service center asking of paid service for the engine.
One more thing, why you are not providing the actual issues in written. Is it not my rights to know what changes you are doing with my scooter in the service center while you asked for too much money for service.
Can you tell me why i have bought your hero duet scooter while it is totally dumped.
Can you please provide the details in written, what changes you are doing with my scooter for whom you asked too much money while my scooter is under warranty.