Bad ring, unprofessional service

This is the third time iv had a bad experience with sterns products told myself the second time I would never purchase there again and I dint, but my fiance unfortunately baught my engagement ring there, paid like R4000 for it, so it wasn't something cheap, it's reason to be upset, silver rings normally don't come with instructions and this ring did, but they dint explain anything to him, and they should have but they did not, not knowing after a few months of wearing my ring turns a black colour, at that moment I was pregnant with swollen fingers and ring cudnt come off, busy washing dishes, took the ring to the cleary park branch, lady and manager says they can't help us, after talking they suggested they can clean it for us and fix it, we should cut it of, okay we cut it off, took it to the Greenacres branch, mananager is surprised that one of her employees did not explain to him about not using the ring in certain products and about chemical reactions that might spoil the ring, they said they'll fix and clean it but we have to pay, he agreed, but they first have to quote us and they said it might just be the same price what the ring cost, before we agreed we said they should first quote us on the cost, they phoned him. And said that it will cost R325, he agreed and told them to go ahead with the repairs, a while later a lady phones to tell him that is not the right price, and she's sorry, like what **** service is that, how can you be so unprofessional, before you phone a customer you make sure you give them the right information now the cost is almost R1000 for repairs, he went back same day probably a hour later to see the manager and then appearantly she left the store, but knowingly she was at the back just didn't wane deal with a difficult customer, they know we can't find the slip of the ring but it's still under guarantee and still offered to help us, it's not a cheap ring anyone can see it, it's so sad to know that these products your selling is so ****,if it's not your watches giving problems or changing colors, or stones falling out, it's your chains, if its not your chains it's your rings,we canceled the repairs because your services is ridiculous and unprofessional, and I hope this time i have learnt my lesson with sterns products