Faulty stone

We bought an engagement ring at Sterns not even a week after that the stobe fell off, we took it back to zevenwacht where we bought it, they fixed it and a month later the ring did the same thing and its not even 3months that we have it, so we took it to Somerset mall and they took it in for repairs. We dont want the ring clearly its gonna give us more and more problems and you cant even assist us. The ring is faulty and its just giving us more and more problems infact we dont want it.