Unhappy Customer

I bought a Silver Square Emerald Cubic Zirconia Ring I phoned the store and spoke to the sales lady she said she would call me back 2 weeks have passed nothing happened. I phoned again this morning explaining the ring has changed colour and the sales lady was so rude with me from Springs store. This is not the first time to experience such bad sales experience from this store. I want a refund or exchange of the ring which was very expensive in the sense that the sales lady did not say it would not change colour she explained it was sterling silver when I purchased it. And now no one wants to assist in the store to refund or exchange the product. I was told she is going to call the regional manager and come back to me and i am still waiting for her call. Never took my number or name so i am not sure which Casper she is calling back.