MTN Store refuses to exchange faulty cable

I bought an iPhone cable manufacture Body Glove on the 25/06/2015 for R299. The cable did not charge my iPad as it took more than 5 hours just to charge 20% of the battery. I took it back to the store and the sales consultant George.Lourens who had sold it to me said they don't do cash refunds. I was then given another cable, same brand only for it to also not work. I had to buy a cable from the IStore which is working fine, so the issue is not with my iPad. The store manger took my faulty cable along with the slip and said itwould be sorted out but I would not get a cash refund. I asked for any other accessories to the value of what I spent instead. But they do not follow up, I had to call, go to the store several times. Now I've been told that they will not exchange it's my problem. As a customer, I do not care who the manufacturer is, I was at an MTN store, the consultant represent MTN, this is bad service and honestly ******* bcos they are selling faulty goods and emphasis on No Refunds. I comply with no cash refund, but surely I should be able to exchange for the same value. Please take note as this will happen to more customers. I just want an exchange for the value I spent