Tablet damaged

Greetings I am absolutely dissatisfied by the service I got in hifi Corp. I bought a tablet at hifi Corp it is 6 months old and the phone is no longer working it doesn't turn on I took it back to the store for repair since it's still under warranty at jabulani hifi Corp.,but only to find out that they wont tack it back because it's no longer covered (within warranty) because it is damaged. I did not take the phone for the buttons damaged but I took it back because it doesn't turn on . I wasn't aware that the warranty doesn't cover that .please assist I am really dissatisfied at this store (Hifi Corp ) as a whole because I usually shop there and this has really proven me to be wrong about the store .