MBPr13 broken? display

Bought a MacBook Pro retina 13 a1502 summer of 2014 in Hong Kong. About a month ago, dropped it from a height of ~ 50cm in the bag and backpack on the floor, no problem then arose, but a small dent on the cover (photo attached).

Three days ago, standing motionless on the table and working laptop suddenly appeared on the screen colored vertical stripes. Bands do not react nor cover the slopes or on clicking on the matrix. Band active, changing only when the screen is something going on. With HDMI output image on the monitor is normal.

Since the laptop is under warranty, carried him to an authorized service center. In the first, the presence of the dents denied warranty repairs, and offered to change the cover from the screen for $ 600. In another - have taken the "diagnosis", which will have to pay ($ 80) in the case of warranty repair. Who sent the photo dents refusal guarantees and seems want money for their "visual diagnostics." Well again, or replacement cover more than half the cost of the laptop.

What to do? To write? Still do not like the situation at the damaged matrix, more like a controller error matrix or video card.