Pink dot on rear camera, phone is in warranty

I have a iphone 12 pro in warranty until November 2022, there was not a single scratch on phone as I have used with a cover always, so I went to apple service centre to claim my warranty , the engineers checked the phone and told me this is due to laser light from pubs and clubs where i recorded them and due to this my camera got damaged, but this is completely wrong , i told them i have never used them to record this types of laser lights from clubs and pubs, hence they said this does not claims in warranty and I have to pay INR 8500 rupees to change the complete camera setup