Refusal to accept a return

Whilst visiting my sister in South Africa I bought jeans at Pick n Pay Blackheath on the 11th of April and wore them to a night out on the 15th of April. Whilst we were out my friend pointed to the knee where they were torn. I am amazed and disappointed. So I returned them to Northgate branch where I demanded a refund because I argued it was cheap quality and having paid R149.99 I was not able to let it pass. A lady called Joyce by the customer counter refused to accept the return she phoned a manager Daddy and he also refused. So I just left them with the jeans and told them to wear them because wasnt going tk carry torn jeans to Zimbabwe.