Hero Motocorp — I am complaining about my hero maestro service

Address:

530008

I am pretty much unhappy with service from the first day i purchased my maestro edge purchased in the month of 26.01.2018 in dondaparthy hero show room sree siva sanakar auto mobiles
1st instance :- they charged additional 600/- by saying some tax the same was not updated while i visited to know details i have visited 3 times to your show room before purchase
2nd instance :- my vehicle use to give 60 mileage after the second service it was reduced to 50 and low
3rd instance :- without completion of one year vehicle is getting rust at silencer rod
4ht instance :- i went bit late for 4th service after the call from showroom i went to showroom i had huge argument for the 4th service
5th instance - i purchased in the month of jan how come invoice date is 22/10/2017
So overall not happy with it request you to confirm how to arrest those escalated issues
Please confirm how to escalate to next level...