Faulty cars

How can you purchase a brand nee car out of the box and you need to send it back to the dealership every week for 5/6 months and they cant find any fault or they cant seem to fix the fault. Then u trade in the car for a ***ond hand car because u having endless problems with the one that was brand new... Only to find that this car also needs to be send back to the dealer because it cuts out. This second car has been returned x2 and its not even 2 months old... To top it off the car was due for service and the cist was R11 000 . Clearly when the car was bought from the owner these things werent checked.. Clearly customer service is not a priority here...