Refused to exchange or refund a defective product

I bought a set of headphones at Pep cell at Eastrand mall on Sunday, 8 November 2015. When I got home, i tried to use the product only to discover that only one side of the headphones is working. Yesterday I went to the store to ask for a refund. The sales assistant asked me the following questions : Did you drop them? Why didn't you come back the next day? Why didn't I test that they working before i left the store. I felt interrogated like a ******** and asked to speak to the Manager. The sales assistant phoned the manager who was not present at the time. She came back and told me that the Manager says that under no circumstances are headphones exchangeable or refundable even if they are defective. I was shocked to learn that i big chain store like pep would have a policy which is clearly in contravention of the CPA. This for me is matter of principle not the R130 that I paid for the product. I actually went to Musica to buy another set of headphones. Please train your people to be able to deal with complaints of this nature properly. I want my refund just as a matter of principle please. My contact number is ***