Hero Motocorp — new maestro average problem

Address:

Mane wadi gate, Junagadh, Gujarat, 362001

I had purchased maestro in Jan 2019 there are some noise in that bike after two service still voice came while driving, and company claim 55 average but my bike average is only 33km per litre I think I had got defective piece from showroom.
I am not satisfied with the piece because my other colleagues using maestro they dont have problem with that and because of this I had taken maestro but I am not satisfied with maestro performance
Need some immediate action other wise I have to complaint through legal.