Warranty Claim issues

In all honesty, owning a mercedes benz is a huge financial inconvenience with no one who can assist. I understand that the warranty does not cover any glass claims, however I have an a200 with panoramic sunroof, the glass panel between the sunroof and the windscreen flew off my car while driving on the highway, the silicon attaching the glass is very much intact meaning the glass was not attached correctly during build, what i don't understand is why such a part is not covered because under normal circumstances there shouldn't be any issues with that panel unless there's an accident or horrible hail storm. I called customer care without any assistance, my car is a 2018 model with warranty ending on the 31st of Dec