There is no way to actually check to see if a seller is legit or not, no reviews to really make sure everything has been going smoothly and no follow up or notification even telling you something was shipped.
You give someone money and then take it on good faith they will actually send it out.
The site does not put any effort into actually making sure any transactions are honored and will not help you if an issue arises.
So often you can expect to place an order, you will never receive it and won't know anything about what's going on, if you contact the seller they will tell you to just be patient they "Totally sent it" but you'll wait 6 months and nothing and then it's too late to do anything about it.
Just don't take the risk, use more vetted and secure things like Etsy.