My 2018 Macbook Pro's screen failed. They replaced it for free, but damaged the webcam in the process.
They told me I'd need to pay over 500 dollars to get it fixed since I could not prove it was damaged while switching screens.
Source: Work at a phone/computer repair store. Mess ups happen but even the technician might not know if they broke the camera, if it was working before, etc. They may just be too low to make exceptions for you and have to assume it was already broken.