Horrible services at Cash Crusaders

I was at Midrand mall buying a phone o had to wait 1 hour just because the person who sells phones was not there then a day later the phone I bought from them starts freezing when I receive or make calls. In some instances it switches of while on call or in the pocket. I decided to return the phone to the shop so as possible within 7 days with all the packaging and the slip. After waiting 2 more hours for the "cellphone sales assistant" to finally attend my request I was informed it that the phone can only be replaced but the back of the slip did not inform me of this nor did the sales assistant. I asked for a refund because I do not trust the phone or the service at that store anymore seeing that at the beginning of the transaction the service was already poor and the goods purchased were not even working. At the moment I just want a refund not another phone not an apology just a refund so that I can buy a phone. The phone is at the store with a copy of my receipt.