Bad customer service

On the 18 June 2019 I went to go exchange my product as it is faulty an there is a 5year guarantee on ..I was told she can not exchange it at is a limit addition an it has to be completely broken...I tried explaining that the flat iron dose not heat up probably...it will heat up wen you put it on yes but while you busy with your hair it goes cold an it never done that ever ...she told me it can’t be changed it must be completely broken