Paying for an item I don't obtain

So, in December I purchased a laptop. Not a cheap item. It was a gift and once opened it had technical issues as all the keys were messed up and never matched what was typed. For example if I typed @ then * would appear. I request that they fetch it for assessment. They sent it back to me and I was shocked with what came back, it was exactly the same but this time with crumbs on the keypad as if they used it as a place mat during lunch and hair and dirt stuck behind the screen guard. I sent it back once again and till this date have not received feed back nor the item. I keep calling and no one can help. All I get is, we will get them to call you back and we are now in May and I am paying R1500 a month for an item I haven't used at all. Durban has just experienced so much and I have lost my job due to the floods. I make sure my payments are always on time no matter the struggles. I even asked for a refund if they don't want to replace it since it was never used by me. I couldn't even set it up as all the keys were off so yes it was never used. I am so tired of calling as well as the attitude of the agents.