Need opinions on breaks squeaking

Hello everyone i legitimately have a question do the AMG breaks always squeak when you break like very loud? I have a A35 sedan and does not squeak But I just got a GLA 35 from the dealership with 52k miles And it squeaks they changed the rotors and brakes and still can't fix it. So am I stuck with this problem or is there a fix? (Got it from a Toyota dealership not mercedes) They also told me they worked closely with mercedes to fix the issue but can't resolve it. They still have it and say they are dipping the new rotors in a special type of coat. So everytime I break It's just a loud squeaking noise.