Not delivered as ordered. What to do?

Hello, I have ordered a Kia cee’d 128 CRDI Spirit with performance package. According to the purchase agreement with the dealer (or intermediary) the vehicle has a consumption of 3.8l/100km and CO2 100g/100km. These details agree with the information on the Kia Home homepage at this configuration. Yesterday I received the registration letter. There are now 4,3l/100km and CO2 112g/100km registered. This could mean that the “EcoDynamics ISG” system is missing, which is available at Spiri I am now somewhat perplexed by what needs to be done. Does anyone know what I have to do about it?