Exact same thing happened to me. Had one item out of my order missing, equivalent to approx 10% of the order cost. When I asked what happened, i received a "Will look into it" and have gotten zero response since. Have you gotten any response?I'm just another new member that came here for this thread. If it matters to anyone, the shipment that I mentioned was late finally arrived. I have no reason to believe I'll have any issues with quality.
I will say that one item was missing from my order. It represents about 10% of the entire order cost. I'll update when I get a response from Qingdao Sigma with how they're going to remedy the problem.