I bought my daughter a stacking set of rings in April, it is early July now. This eas a bday gift. One of the zirconia stones fell out and the ring became misshapen. However the other ring did not change shape. The sales assistant kept emphasising that my daughter should never sleep with them on, because our body temperature increases during sleep and changes the shape of the rings... I had never heard such nonsense in my entire life. In the end, she told me to Google this a little more (regarding the body temp) and decided to replace my daughter's ring. I was very disappointed with the attitude and tone with which we were faced with. If the outcome was not in our favour, I would have taken things further, but one thing I am taking away from this is that they have lost 2 Pandora customers.