Possible fake ratings

Hey guys, please help me understand what is going on!

I noticed some 2 and 1-star ratings (not reviews) on my product and I cannot see who’s left them in seller central. They do not show up with the rest of the reviews. Is this because:
A - you cannot see who’s left a rating at all
B - these are from unverified purchases and that’s why they do not show up in seller central. If option B is true, these are fake, as I only sell on Amazon.

The ratings were left twice on my account and on the same day. Both times they brought my review to 3.8. First time this happened I just wated slowly to gather positive reviews with time, which I did. Got my rating back to 4.0 and then got a new batch of 1-star ratings (left on the same day) which again brought down the product rating to 3.8. Previously, I’ve had a 4.6 rating for a long time and good Vine reviews so I know the product isn’t bad quality.

Is there any way to check who’s left the ratings and if they are a verified purchaser or not? This just seems too suspicious and I know that the Chinese review factories also have a service for negative reviews for competitors. I am in a niche where all top competitors are Chinese manufacturers and I have my own private label.

Is there anything I can do? Someone I can contact? Can I stop unverified reviews and ratings on my product?