I am not knowledgeable about this particular ring or brand but r/repladies on reddit has some members that left reviews of what they purchased. They disclose where they sourced the ring and give a review of what they received from the trusted sellers.
Reddit is your best bet for this, you'll find subreddits with private sellers and you will be able to contact them directly. Avoid aliexpress. Taobao can be usefull too.