Pathetic service

Bought a hair straightner on the 30th from Clicks Jeffreysbay Fountains Mall however after using it once I experienced that it didnt do anything to my hair so when I took it back to exchange to a different one I was told by the supervisor that due to it being used I cannot exchange it to a different one and in the same breath also saying that they dont make this make(Safeway) anymore, I stated to her that my previous straightner was also not working properly and with it also being used once i was able to exchange it and still pay in for a better one. I have never experienced such bull **** service in my life and working in a retail store myself this is totally unacceptable i didnt even have the straightner for 7 days. I havr left received with straightner in store refusing to take it back as it has no use for me if its not working up to my standards. This needs to get sorted out ASAP or else I will be taking further steps or just give my money back and I will go to a different store which will help their customers better. We shop there on a regular basis but if this is service than i will rather not go there anymore!!!!!