Manager shouting at me. Extremely rude.No manners

Good day. I returned cellphone cover to the Telkom store at Baywest today and found the Manager, Nom, on duty. After waiting about 15 minutes for her to appear she told me that there was nothing wrong with the cellphone cover and that I either manhandled it. Or that I dropped it. She started shouting and did not want to hear anything I had to say. She was utterly rude. She did not care about how she was speaking to me in the presence of other clients. She was completely disrespectful. She did not listen to anything being said and refused to refund. . Cover was less than a week old when it started to break. It was obviously a poor quality item Is this the norm for Telkom store managers to treat clients like ****. What about the policy that the client is always right