cannot pay for damage goods

I bought a wedding ring from browns jewelry shop in menlyn end of september2017 worth R3100.00 I got married on the 16th of November 2017. On the 4th of January 2018 one of the stones on the ring fell off. The ring was taken back to store . We were charged for repair fees. I then expressed my wishes of returning back the ring and getting my money back as I don't trust in the quality of the ring. I was told I cant according to their terms and condition that I find to be unfair as I cant spend R31000.00ON A RING then after 2 months of wearing it. It needs to be repaired. i want my money back please assist