Mecer Laptop & Vodacom

I took out a contract with vodacom for a Mecer Guru laptop. It has been giving me so much hassles whereby the laptop will randomly start displaying either a full/partial black screen while typing and it also recently starting shutting down randomly when not plugged it. It then takes endless attempts to turn back on and struggles to charge thereafter. Am I expected to continue paying a laptop contract with a laptop that does not work ??!!