The policy is covering the shop's butt and not the consumer's!

On the 29/12/17 I bought a panty, washed and wore it the next day. When I took it off in the evening it showed signs that it was old and been worn a couple of times. I washed it again and went to complain at the Jam Clothing in Meadowdale Mall. I was informed that their manager was not there. I was asked to leave my number so that they call me on their decision. I saw a missed call but I never thought it belonged to the shop as there was no message left. I then drove to the shop as I was in that area, I was told by the Manager that they unfortunately cannot change nor refund me as it was against their policy. "We cannot change it due to hygienic reasons", they said. I agued that the policy covers the shop but not me. The shop had my money and I have a product which I was not content with. I was therefore told by the Manager that if I was not that happy with their product then I must not shop at their store, was their response.