Honda Cars India Ltd. — Honda amaze - mileage problem (16. 3 km / l only)

Address:

Kottayam, Kerala

My name is Jose Philip residing in Kottayam.I had purchased Honda Amaze (Diesel) car from Vision Honda Kottayam, year of 2013 Jun. Vehicle information : Model: Amaze 1.5 VX MT (I-DTEC), Chassis No: MAKDF23FDN002256, Engine No: N15A12010138 . We didn't get mileage properly after completed our first service of 10000 km we gave complaint to the dealer and they don't take any responsibility for clearing our issue. we make our car several times for service, and the company authorised service center (Vision Honda Kottayam) didn't clear our issue. our maximum mileage is 16.3 KM/L and the company advertised that they are providing 25 and above KM mileage for the Honda Amaze.
Kindly arrange immediate solution for our mileage complaint