Renault

We bought my daughter a Renault. This vehicle has made a terrible sound when in reverse gear from the day we purchased it. Upon returning the vehicle to the dealership it was explained that these vehicles have a known fitted factory fault that we should just get used to. So my question is how is Renault allowed to sell vehicles with factory fitted know faults? My advice to anybody wanting to buy a Renault ,JUST DO NOT BUY THESE RUBISH VECHILES