Bad mileage for amt version 10kmpl

I brought the Amt version and its mileage is horrible. I m getting 10kmpl in city. I do not use it for long trips. On taking up thr issue with the service centre they say u only get the said mileage when you drive constantly at 50kmph and without too much acceleration and braking. So basically under perfect driving conditions which I dont think anybody will get on indian roads. Renault takes us for fools? Giving crappy excuses to cover up their incompetency.