Declined warranty claim

On the 3rd of May 2025 I took my son's A25 2024 model phone in for a screen that is not touching. This is at the Eastgate Shopping Centre The lady game a form and I filled it out and she asked that I please send them a proof of purchase. I emailed the proof of purchase. A few days after I sent the proof of purchase I receive a call that the phone was accessed and it was found that it a small dent on the rear cover near the camera and given that the warranty will not be covered. I asked the lady what does the rear cover have anything to do with the screen not touching as the two components are very far apart from each other. She further tried to make it as if I knew about the damage when I lost my cool as too how can they say it has a small dent and it could have been them that dropped or damaged as she claims it's a small dent not visible the naked eye. I honestly don't understand why and how the two components could affect each other. I'm nor techy but I know the only connectivity between the two is the body and feel this is just an excuse by Samsung employees at the Eastgate Centre trying to make their sales target by declining warranty claims and I'm sure I wouldn't be the first . I would like Samsung to please investigate this matter and honestly check on the Staff at Eastgate. I honestly disappointed in this kind of service from such a big reputable name. I have a phone from a different manufacture and it has fallen so many time I lost count but nothing affected the touching of the screen. I've had other Samsung's in the past and they too performed well no issues. My concern is the claim being declined because of a small dent on the rear cover .