12 Karat ring only has 4% gold content instead of 50% gold content

I bought a 12karat gold ring from American Swiss in Mall of Africa. It is supposed to be made if 50% gold. I am currently on a trip assessing gold suppliers and they use a XRF machine to determine the gold content. The composition of the consignment was 96% at 23 karat. My ring contained 4% gold and consisted of mainly lead.

12 Karat is supposed to be 50% gold. I will never buy from thus company again. This is *****