Tata Motors — millage

Address:

Kolkata, West Bengal, 700040

My complain when addressed was not resolved as they can not do anything with the mechanism as it is all computerised.
If mileage is very poor, that is what will be.
If want better mileage, then shift and drive only in highways with speed of 40 to 50 kmph, which is ridicules.
I don't know how was my previous complain resolved without providing a solution and justifying the poor mileage of less than 10 km/lt which the vehicle gives against big claims of high mileage 16km/lt in town driving.