1/ Go to the local jewelry appraisal agency to identify whether it is natural or not. If it is natural, don't regret it. After all, unlike gold, precious stones can't be bought at all times. Buying natural jewelry actually depends on fate. 2/ Generally speaking, there is no problem with the quality of larger jewelry stores in Thailand. The most important thing is to believe that what you have is the best. 3/ If you still can't get over it, keep it. The next time you come to Thailand, bring your jewelry and the invoice book at that time, and wait until you get to the old shop. They should get it back, but there are some handling fees, which may be around 10%.