Screen crack internally on its own

My daughter has a M1 Mac book air purchased Dec 2020. Screen glitched with lines in august 2021 sent it in. Sent it in for a second time in Oct 2021 for the same issue. Now in December she open the laptop and it’s lines again. We immediately took it to repair and the say it’s an internal crack that’s our fault. 650 to fix. This is ridiculous. She literally opened the laptop and the screen cracked. We couldn’t even see or feel the crack until the guy from the store rubbed the screen.