Damaged laptop after repair

Hi booked my dell laptop in for repair due to the keyboard not working. The laptop was in the 3 year warranty. When I went back to fetch the laptop there was damage to the laptop lid and a mark on the laptop screen. The store refused to take responsibility since the repair was done by a 3rd party. This, even though Dion Wired facilitates the entire repair. When the laptop was booked in, none of these damages were logged thus the damage was done by the store or the repair center