samsung note 8 black dot on screen

i bought a Samsung NOTE 8 cellphone 6 months ago and notice a small black dot on the top left, i actually thought it was part of the side display. over the months it has got bigger and thought i send it in, the technician said it was a default on the screen and started booking it in, after close inspection they noticed a small crack at the bottom right hand side of screen hardly noticeable. i was then told all guarantee has fallen away and they cannot fix the dot as its there policy that if the screen is damaged in anyway they cannot fix it. i find this really unacceptable as the small crack has nothing to do with the defect screen, i have also googled and seen this is a defect on Samsung phones. Im not going to let this go and will take it further,