I watch screen falls out

My screen of my iwatch fell out and I went to Apple store. The guy looked at it and seen no damage. He came back to me and showed me a mark on my watch surround calling it an impact mark. There was no mark before it went to workshop but it was quite clear on return. Also he says the battery hadn’t swollen. How do I know he did not show me a swollen battery to compare. The screen obviously had lost it adhesives around the holder which is why it came out cleanly. I have to say I was very disappointed in the response to my faulty watch. I still upgraded my watch but I have to say I have no faith in Apple repair. I feel as a customer with rights I deserved a better service.

Sean