ok so like 3 weeks into having a new macbook, i was skating on my campus and my board caught onto something. well my friend found a dent on the side by the power supply of the laptop and the same side of the screen. and there's a tiny crack right above where you plug in the power supply. i went to my university bookstore where i bought the macbook, they said they can't replace it for me because it was my fault and not a hardware problem. so how much will it cost for apply to just replace the casing? also i read online that the discoloration of macbooks were you place your palm is a hardware defect and its at fault with apples part. is this true?