damage goods!

I am so disappointed. I got these beautiful tempo watches as gifts and they were both purchased at Sterns. They are not even a year old and some of the diamond stones have already fallen out. The first time it happened to one of the watches I took it back hoping that they would repair it just to be told that it cannot be repaired because the diamonds are not guaranteed. I let it go but then the same thing happened to the second one. This is no coincidence and what am I suppose to do with these to defect watches? Is Sterns selling poorly made watches? These watches were bought at a high price so the people who bought it for me expected high quality instead they got two defect watches. This is ridiculous,I'm so disapointed because now I'm afraid to purchase anything there