Kalyan Jewellers — Product : Solitaire gets off from the ring

Its very unfortunate that a solitaire ring which was bought few years back with a trust that a good brand like kalyan will provide quality product.
But yesterday my wife have seen the solitaire missing from her ring and we all are in disarray and can't imagine that something of that sor can actually happen.

A similar product from a local jewellery shop is still going good and i never before faced anything of this sort.

Now the queation here is, Who is reaponsible amd who's pay for this loss !!