How's the airflow from the airvents. (Check for any leaks in vents air piping) What was the temperature at the grill after switching ON the AC after 5 mins. It should be below 4C. ( When I got it checked it was 2.3 C - 2.5 C) My Linea MJD chills the cabin completely within 10 mins even when temperature is above 40 C. Why dont you try the AC of demo car. It would clarify if your AC system has problem or not.