2015 Ford Focus flat tow damage

Ford states on page 185 of my owners manual it can be flat towed . I tow this car for almost 5yr with over 50,000 miles towing . You are right Ford didn't know full grasp of the stresses involved . Don't you think Ford should responsible the design problem . If this happen going down the hwy it could have been a serious accident . The car was still under warranty and Ford would not even look at it . How can we let people know this could to them with a Ford Focus ? Ford customer service would not help me, I tried to to tell them about my problem and sent them photos they hung up on me . I will never buy a Ford again .