Secondly, your certificate is quite different from your present certificate, but as can be seen from the remarks, the marked weight of diamonds is 17.2 points, which is 20 points less. The state stipulates that diamonds with more than 20 points must have a diamond identification certificate when they are sold. Since this is less than 20 points, it is not illegal for merchants to issue certificates for diamond rings.
Third, the certificate is issued after the diamond ring is inlaid for identification. Because diamonds can't be disassembled, they can't be weighed separately. The correct way is to indicate the marked weight on the ring bracket in the remarks.
Fourth, whether this diamond is shoddy or not depends on whether the price is determined according to the purity of cracks and flocs when the merchant sells it. Because of these defects, the clarity of diamonds is definitely affected. If it is priced according to the correct clarity grade when it is sold, it is far from shoddy. However, as you can see from your description, the basic seller bypassed the problem of clarity in the sales process, so if you sue the merchant for fraud, the evidence should be insufficient and it will be more difficult.