Broken diamond ring what are my consumer rights?

[diamond4eva]

My husband bought me a diamond ring in January 2007 (not very bling or expensive but I like it never the less) made with several very small diamonds. In May I noticed one of the stones was missing. I returned it to the store (Jones and Ernest are on the shop's name!) with my receipt. They sent it to their repairers to look at and have today told me they can repair it but due to wear and tear I will have to pay for the repair which is half the cost of the ring in the fIrst place even though only 1 tiny stone is missing! I had the ring 5 months and admitedly wore the ring a lot but I thought rings were there to be worn not just looked at.
Any advice would be gratefully received