First off, I would be very careful about posting a post like yours - you are inviting bad actors to contact you with a "great deal", which might end up not being so good at the end of the day
I don't really know the Chinese suppliers on here intimately since we don't work with them - But if you go through the boards you will find 2-3 that are consistently mentioned with positivity: Their tests are spot on/good enough, and they deliver on their promises, reship if the package is seized etc.
As
@milos mentioned, start with the list
@dionysos has.
Instead of trying to save 5-10$ per vial, you are most likely better off going for a reputable vendor, than taking a long-shot with someone priced significantly lower.
You will also see a few complaints here and there - But from my perspective that's more about the customer not really understanding the market they buy from. The supply chain from most Chinese vendors is very hierarchical, margins are pushed and standard practice is not similar to what you would expect when ordering from Amazon for example.
In my opinion, going for a vendor that has increased their prices slightly, is probably a good idea - It means they are established as a supplier and don't need to scrounge for cash. So you're less likely to have any issues with them - And they have a reputation to maintain