Kia Motors South Africa
Kia Cerato 2.0 fuel consumption

I have the same problem as a lot of people on here about kia fuel consumption.
Cerato 2.0 AT fuel consumption terrible. What I want to know is is there anything one can do to fix the problem?
Surely this constitutes false advertising? ALso we can't do something about it ourselves as you will void warranties on the vehicle?

A response from someone at KIA SOUTH AFRICA would be appreciated
(Supplier name changed from Kia Bryanston to Kia Motors South Africa by Hellopeter.com)