Refusing to pay on baseless conclusions

My car handbrake couldn't disengage and had to be towed to the nearest Mercedez Benz centre, where they took pictures that showed there was consequential damage to the bearing and backing plate due to part of the brake pad breaking and being loose inside the disc drum.However they refuse to pay their portion for the damage claiming the car was driven for \prolonged periods"with an engaged handbrake which is a baseless and ill-informed conclusion by a \""technical specialist\"" who has not seen the car but saw pictures and that i cannot speak to. There is a contract that Mercedez Benz should honour under the Mobilo120 maintenance plan and they are plainly refusing to honour without any valid"