Game refused to change my Kettle

I bought a Kettle last year June .Yesterday I took the Kettle back to the store as it's no longer working. I was told there can't help me without a box????What does a box have to do with exchange??The Kettle has a 3 year warrant. The lady didn't Want to listen to me because of a Box.I am disappointed with this. A FRIEND of mine had the same problem earlier this year, and was helped. So I don't understand how this works!!!!!!