I read you post on T.A where the Jeweller was named. It is a Jeweller, I personally would not use.
I have a Zultanite ring, bought in Calis. I also have a full receipt which gives the stone, the diamond details and weight,also the Karat of Gold. it is dated and signed with a Jeweller's name, address and phone number.
If you get a receipt and you find out the piece of jewellery is "wrong" you then have redress.
The question is, do you have a full receipt?