Problems with Apple Care Supervisor Germany

I have a complain about my 3 year old MacBook Pro with aluminum migration (pimples) on the LCD cover.

Apple support send me to the next Apple Store (Hamburg, Germany). The metal migration was analyzed by Apple specialists at the Apple Store. They reported that this metal migration is not my fault, it seems that the problem comes from inside the display cover. A report was written, Apple Store Hamburg asked Apple Care to take responsibility to decide next steps.

Next day i called Apple Care and got connected to the supervisor. This supervisor rejected any obligingness because my product is already 3 years old, out of warranty and this is a cosmetic damage.

My question to the supervisor, who will be the next higher person for this decision was answered: There is nobody on a higher level at Apple Care for technical decisions .... "i´m the top supervisor"......

I can not accept this decision because this problem is definitly a manufactoring problem of the aluminum case (according to the employees at the apple store).

I´m now struggeling between Apple Store and Apple Care and have no idea who will be the right person for my problem.

Is there a management team in germany i can contact?