Fuel Consumption

My car (Grand i10 2015) was serviced on 11 Jan (1st service) and after the service my fuel consumption sky rocketed. I contacted them and they booked my car in on the 18th where they regapped my spark plugs and did a fuel consumption test. No faults were found. I then drove the car for a few days and still the fuel consumption was high. I contacted them and the car was booked in again on the 25th and the reset the adapters and cleaned the throttle.... and still fuel consumption is high! I logged a complaint on the Hyundai Website last week and to date nobody has contacted me. I cannot afford to waste money and I specifically bought a car with low fuel consumption. <br>