Bike parts changed during the services

Location/place: Vijay Nagar Ghazia bad

Name of company/service: Bajaj two wheelar services

Hi Sir/Madam,

This is Mahesh Kumar, I have get serviced for my bike at Bjaj authorished service station at Vijaynagar Ghaziabad Nr Vijay Nagar police thana,
They have done something wrong with my bike, guess they took my bike’s original parts and put something else resulted which my bike is running very badly, petrol average become 50% lesser than it was giving earlier, I have coplaint 5 times at service centre but no positive response.

Kindly help me to resigter this coplaint againt Bajaj Service Company.

My details are as below;
Mahesh
Bike- Pulsar 220 (UP14 AX 4527)
Contact # 9911734007.