I demand a full refund

When I got my Twisp, end of October 2015. I was told is had a 6 month Guarantee.<br> well its been 3 months, and its broken. either doesn't charge, or when it fully charged, doesn't burn. i have been to a Twisp Kiosk, they refuse to take it back, or even replace it, because off course it works when I am at the Twisp Kiosk. so my word is not good enough.<br> <br> Please refund me in full ASAP. I will gladly return the device. I was happy for an exchange, but I don't want one now, the service is **********.<br>