WEDDING RING CHANGES COLOUR LESS THAN 5 MOUNTHS

HI, On the 4 April 2023 I went to Sterns in Bethlehem I believe I was the first customer that day we bought a set ring for our wedding which was happening on the 30 April 2023 we paid using my husband TFG account, on the 7 September I noticed the ring was turning Brown I was shocked I couldn't sleep I was beyond stressed and disappointed , on the 09 September i headed to Mimosa mall STERNS where a lady assist me and asked if I had used a strong chemical which I rep**** NO, she then polished the ring and recommended I buy the Ring cleaner ,I was excited my ring had retained its colour again , 30 minutes I got home my ring was Brown again. I'm highly disappointed and sad at the same time because I have not been married for even 6 months but yet my ring is faded, i need a refund or replacements, if it was any other ring it was going to be fine but mow its my wedding ring , please assist because I'm not okay.