I don't know about the warranty only covering stones. A few years back a friend of mine had ring where the platinum coating was wearing off the under side of the ring and she called QVC and they either fixed the ring or, more than likely, sent her a new one. Can't really remember which one. This was maybe 4 years ago. She didn't have her paperwork anymore either. Maybe speaking to a supervisor would help.
“Memory is a way of holding on to the things you love, the things you are, the things you never want to lose.”