Ford Dealership Gezina review: Stole my phone

Forgot the phone in car for replacement of brakes when I phone to inform them the phone was gone Samsung galaxy A21. when I go to them they tell me that they cannot be held responsible for the phone that was left inside the car it is my duty to remove all valuable thing but my argument was if I forgot something does it mean it must be stolen. They said they are not accounting for that please help me