no warranty on goods

I recently purchased a screen protector and back cover from Shop L186 Vodashop at Southgate Mall on 13/02/2016.I was assisted by Samuel to fit the screen protector.This morning 17/02/2016 the screen protector has cracked,so in the afternoon I went back to store and I spoke to the manager(Thabo..)he arrogantly said his store is not responsible and he accused me of dropping the phone which led to the crack.if I dropped the phone I wouldn't have bothered to waste my time and petrol going to the store.Had Samuel fitted the screen protector correctly this wouldn't have happened and irs barely week.Why wasn't I told that there is no warranty when I left the store,meanwhile vodashop at Clearwater has warranties on their goods.