Power cable faulty

I bought a laptop on exactly 31 October 2014 at game Cash. In December the charger was faulty as would not charge the laptop. i took it to my nearest game stores and it was booked in. I only received it after 3 whole weeks and everything was fine. i didn't complain then. now again the charger is faulty. its doing the same thing it did the last time and im told the charger is not covered!!! why was it covered then? Why should i pay for a new one? what does the warranty cover? What is warranty if it doesnt cover the power cable? i need answers ASAP. R4000 is alot of money for it to be thrown down the drain