different colour

My car was booked for repair at automagic Gezina to replace the front bumper. After collecting the car I noticed that the colour of the replaced front bumper is not the same as the colour of the rear bumper. Firstly when I brought this matter to their attention i was told that it is because the paint has some glitters which did not make sense to me. I went back to automagic and spoke to fransior and he inspected the car. He called Shawn who also inspected the car. They told me that the colour of the car will not be exactly the same because the body of the car is made of metal and bumpers are made of plastic. I agreed, however my problem is that both bumpers are made of plastic and their colour are not the same. The replaced front bumper is darker than the rear bumper and the mirrors are also made of plastic and their colour are the same as the rear bumper . Shawn told me that he need to take my car to hyundai (dealership ) to verify the colours. why does it have to be a hassle for automagic to fix this paint issue? I am so disappointed.