Kays Jewelers jewelers stroudsburg Pennsylvania

I went to two different stores to return or exhange this pendant. I finnally found out that the pendant was not black diamonds at all but rhodium uunderneath the diamonds. I went to a jeweler to get it cleaned the black completely came off I was shocked and my jeweler is a reputable jeweler cleaning for years. My pendant was dirty and they have free jewelry cleaning with a purchase so I had my pendant cleaned and low and behold the black came off. I thought they were black diamonds it was advertised that way so went to one store they didn't want to exhange it or even have the rhodium put back on there free because I just brought it in July they have a three month return policy so now u have to pay for the cost of the repair and the customer service was horrible her reponse at the second store was, they damaged it so we have to return it. I don't think so. I'm like I'm the customer and its still under the return policy. What happened to customer first after its advertised as black diamonds and it isn't then she said no one told u it only has to be cleaned with a cloth and not worn everyday....I'm like no! Why can't I wear my pendant everyday ?