Sterns vangate mall

On the 24th december 2017 I bought a silver chain with a stainless steel pendant. Six days later it changed colour. I returned it to the store I purchased it from. STERNS VANGATE MALL. I am so disgusted by their service. Nandipha and farah told me it will be sent away to be checked out. Two weeks later they called me to come and get the item. I got at vangate mall on the 15th january 2018'.-and was told the supplier polished it as there had been deep scratches that caused the pendant to change colour. I then asked the stores assistants_= NANDIPHA AND FARAH. What was the cause of this changing colour they told me the acid in my body. What an idiotic answer. How exactly can acid in a persons body be the cause for the stainless steel pendant to change black. Since when do acid in your body cause silver ans stainless steel to change colour. Im very very angry and upset. Nandipha called her manager to tell the manager I want a refund. The manager told nandipha I cant be credited with a refud I have to take something else instead. I am very dissapointed as the return policy shows...if the goods are defective you can return them within 6 months of the date you bought them. The goods must have been cared for. It will be replaced or refunded in the same way that you paid for your goods. Im highly upset ,to think this is a 6 month policy and I had it only for 6 DAYS.!!!!!!! They never gave me a option of refunding me. They told me I MUST just take the polished item. All I want is a refund. I refuse to take goods that they just polished , as to my knowleage if a item changes colour then that means it will just change colur again. They only polished the item that had deep scratches in!!!!!! I would like this issue to be resolved. ITS THE FIRST AND LAST TIME IM EVER BUYING AT STERNS AGAIN.!!!!!!!!!