Look, these people are either completely incompetent or dishonest, or both, You need to find out what it takes to get a "stop work" order and get that car out of their possession, and get it documented, IE a witness who carries some weight, and photos.
The damage sand does to bearings, brakes, chromed shock shafts and seals is not only an "end" to the component, it could be argued it's a safety hazard.
