Look is good but mileage of petrol variant is very poor

I purchased from surjit Hyundai, kolar road bhopal It was very bad experience, don't believe on verbal communication with executive they promise a no of things during buying and during first service but later on they did not provide anything. Look of the car is very good, driving experience is also good but lac of performance and most important is fuel efficiency is very bad, its only 11 km/l in city and 13 to 14 km/l on a long route, never go for a venue petrol, it is a big mistake which I have done and never believe on sales executive/Manager they don't have any knowledge, please research your self by online reviews and online platforms websites. I am very disappoint to purchase Venue petrol 1.2 S++.