After 10,000 km brake discs defective – no culant !!

Hello Fox drivers, the Fox of my mother is only 15 months young has about 10,000 km (daily use!) down and when braking from about 80 km/h everything vibrates like crazy in the interior. Drive to the VW dealer: Brake discs are rusty in various places (hence at these places thicker), therefore the vibrating… Statement: Wearable part, brakes were used too little…^^ etc. no culant! Has someone ever had experience or similar problem and culant se itens VW? Would be by far the first KfZ which has broken brake discs after this mileage…is simply incomprehensible and indicates poor material quality. thank you for suggestions and or opinions