Clutch defective after 25.000 km

I have been driving a Mini Cooper D, 2009 for about 2 years. After 25,000 km of mileage, the clutch and flywheel have now been replaced – cost 2,100€.- The workshop has submitted a bulwark application, which was rejected without comment by BMW. An employee of the workshop said that this would not be normal, because the clutch is not only burned, but lacks the flexibility of the surface. His colleague, however, said that this would clearly be a burned clutch and the pieces would be burned due to the large Can someone tell me if it’s normal that pieces of the clutch lining are missing? How can it be that a clutch is already broken after the low mileage and the flywheel is with me. I’ve already had some cars and never had any problems with a clutch before. I’m thinking about turning on an expert – does anyone have any experience with it?