Cleaning the diamond ring with an ultrasonic drill may really shake off the small diamond. You should take out the evidence and invoices dropped during cleaning in the store and tell the clerk the problem with a tough attitude. If you can't get a satisfactory answer, go to the industrial and commercial bureau.

In addition: the free maintenance mentioned by the subject has nothing to do with this lost diamond. Free maintenance means that the ring is deformed and it is impossible to make up the lost diamond for free. This cannot be used as an example. As long as the drilling process is emphasized, the drill will shake off the small drill.