Faulty diffuser not replaced

I purchased a feather the owl diffuser for my daughter's birthday and it was such a disappointment when we discovered that the unit was faulty and not working at all. When emailing them I found that the email addres wasn't working and after sending an email to various emails addressed I phoned them. They then send me a trouble shooting email to reset the unit which I couldn't do as it was not working at all. They also recommended cleaning the unit but it's never been used. I tested the power cable and this seemed to be the problem. When communicating with them telephonically they wanted me to send the unit back via courier at my cost. When explaining that the power cable was faulty they wanted me to pay for courier cost to replace it. They sold a faulty unit and expect the customer to pay more to replace it. Really shocked that they are not prepared to pay for the courier cost if it is faulty! I was told that a manager will contact me but have not received a call to date and still have faulty unit!