About the very bad mileage of this car

Look and Style- Very attractive looks....... its interiors are also very attractive... its interiors are like i10 Comfort    Pickup- Mileage I m very disappointed with the mileage of this car... I'm getting around 9 to 10 km/litRE in the city...and on the highway its around 14 km/litre..... I have gone to the workshop for the mileage two times..., but they don't do anything.... just change some settings and told me that from now your car will give u around 17 km/litre in the city.... but the facts remains the same. I m still getting around 9 to 10 km/l in the city... in my opinion no one will go to showroom to purchase this car... its the bad car ever the Hyundai has made.... in showroom they will tel u that this car will give u around 20 km/l in the city... they all lie.... if any responsible person of the Hyundai company read this review please help me out of this problem... otherwise I have to sell this car....i can't afford this car....