Half mileage as promised by company

hey guys, i have bought this car 2 yrs back. this car is really not good for tall peoples having Height 5 feet 8 inches also. very less leg room that i cant drive this car more than 300 Km continuously.its mileage is also not good. i am getting only 14 km/l only. this car is not comfortable for family of 5 as no one can sit properly. if front sit passenger sits as per his comfort then there is no space for rear passenger. its pick up also not good.if we cross the speed 100 km/hr then the car is like flowing in air. car build up quality is also not good. very cheap material is used to built this car. only good this is the maruti brand name and service I have bought this car for 4.5 lakhs with addon some accessories. in my opinion, spent some more money and buy Tata Tiago.