Defy don't want to replace thier faulty refrigerator

I am having a horrible experience with a Defy fridge that I purchased a year ago. Upon delivery we discovered that the refrigerator was not working and was not balancing well , we contacted Defy who sent their technician. The technician fixed it but we were not totally happy since it was making an unusual noise. Now the fridge has stopped working totally and we have asked for a replacement since this refrigerator is evidently faulty. We have called defy but they are now refusing to replace and they want to blame us. There is no damage on the fridge and the warranty is still valid.