KIA bad service/ sale of damaged goods

I am really disappointed by Kia. I bought a brand new Kia Rio this year in February, when I got home I found out that the rear windscreen had a scratch. It them months to replace it after I fought tirelessly. When they finally decided to replace the windscreen they now scratch the vehicle itself, not even one small scratch but many. I have been fighting with them even today. They keep on saying they are waiting for a slot to book my car in.