Mileage is poor

I have bought kia seltos almost a month back, the car is smooth in driving, it is loaded with many features, the only I m not happy with is the mileage, company is claiming 18 for auto but in cities, u hardly get 9 kmpl, on the highway the car gets around 13kmpl. If u don't have much to do with the mileage then this is a perfect premium car at this cost.