Damaged goods

So I booked in my mobile device to Hauwei to have my screen replaced and when I received the quote it stated that I need to have the back replaced. Strange thing is, I had the backcover, camera and charging block replaced and then the screen gave in. When I questioned then and they sent me the book in sheet it stated the back was damaged, I asked for a picture and the back is F'ed up. Hauwei is not taking responsibility you probably wont as well, because you guy never even marked anything to state that there are no cracks on the phone and asked us to sign. Yet I trusted your businesses now I am worse of after spending Thousands to have the camera, charging block an back repaired I am back to square 1, **** the phone away. I want an investigation to be conducted and to findout where the device was dropped and damaged.