Ring color change

My purchased wedding rings on the 18th of September 2021, within a period of 6 months my husband ring broke, we took it for repairs they charged us R847. On the 12th of September 2022 my rings changed color, on the 13th I went to the store, they took it and cleaned it saying maybe it's sanitizer. They even advised me to buy jewellery cleaner and bought it. The following day the rings went back to change color again, I lodged a complaint via telephone to customer service centre,up until now I haven't got any response, it's a 3 piece 5 ct gold rings. Please assist as I took the ring off my finger bcz I can't wear it. Pamella Zuma