Nokia — Poor Customer service

Hi, I'm Rahul from kozhikode, kerala. My father bought Nokia 7.1 mobile 6 months back in January 2020, it still has 6 months warrenty. Everything was fine until 5/8/2020. The phone suddenly doesn't charge beyond 10%, to rectify this problem, we visited nearby Nokia authorised customer service ( i have attached its address below). so, what happened was, the service centre claims that, ' warrenty cannot be issued, because the phone has a small dent on top right corner '(i have attached the same below) i don't know what it has to do with my charging port issue. The claim 1500Rs for changing of charging port, eventhough i have warrenty, it shall be viewed as null because of this small dent. I hope they explain the meaning of warrenty, and what it has to do with my phone's complaint. They are just aiming to null my warrenty, which is my right for free service. I hope i shall get justice and those in the service centre shall face the consequences of their action and poor behaviour.
I have mentioned my phone's Imei and other details on pic attached below.