i got a chassis system fault error on the screen, car stopped

i went before to maintenance to check a sound in the front left in the car when i accelerate the car starting from 30KM/s to 60 KM/s and he told me to get the car again in another time to check it again because they hear the sound but they don't know from where this sound appears. and after few days in a hot day and when i was using the conditioner the car give and error and stopped taking any respond from the fuel hand so i cant move with the car which is weird its a 2.5 month new car 2015 Japaneses model. so this is not acceptable to find in this car and after i went to modern motors in smailia desert road in Egypt and tried to start it after it cools the car starts with out any warning so they connected it to the computer and get the errors stored in the car and they told me to leave it for checking and after 2 days they told me that they tried it and the error didn't appear again with out fixing any thing in it and give me 2 choices, to take it and i feed them back if the problem appeared again (its not a professorial way at all and that must not happen) or leave it fore more checking for another 4 days which is a long time to check a problem using a new technology car and tools so (they already got the error report from the computer connected to the car) so i need an immediate solution and answer to this problems or get me my money back