Mercedes
If the car is faulty I would say it's not of merchanabe quality and wouldn't think it was fit for purpose the car is not that old so I would not say it would be a ware and tear issue there are cars on the road many years old with original fitted parts and are not worn out I would stick to you guns and say you want a replacement or your money back as you have no faith in the car as I have said you don't buy a newish car and have to buy new parts so soon have the factory fitted poor quality parts good luck and don't let them talk you into paying for parts or a good will gesture unless it's in your favour