Invoice is important evidence. If it is lost, it is very difficult to claim. First of all, there is no evidence that the ring was bought in this shop. Even if it is a brand, they have to admit it, but they can't prove when they bought it. It can be said that it is a normal phenomenon that jewelry wears naturally for a long time.
If the bare diamond stone is not lost, you can look for the store to maintain it with the purchase invoice, because in the jewelry industry, the 50 yuan 1 yuan gem may be 500 yuan, because the jeweler has included the after-sales service fee. So, if you find the owner, you will definitely help repair it. You can also change a ring of the same specification.
But if the diamond is lost, it will be very difficult, because the diamond in the diamond ring accounts for a large part of the cost, so it is probably impossible to return it. Because there is an unwritten rule in the jewelry industry that "once the goods are delivered, they will not be returned", mainly because of the preciousness of jewelry.