The clearest sign a clinic or facilitator is not verifiable is that it cannot show you a named surgeon, written payment terms, and a written recourse path before you pay anything. Below are the five signs worth checking for, in order of how often they show up.
If the contract does not name who operates, nothing stops a substitution: the exact failure mode "ghost surgery" describes.
If the quote, the deposit and the refund conditions are not in writing before you pay, there is nothing to hold anyone to when what happens does not match what was agreed.
A verbal promise is not a claim path. If something goes wrong, you need an address, a representative and a signed agreement, decided before you travel, not after.
A claimed credential you cannot check against a public register is a claim, not a check.
Korean law forbids patient testimonials in medical advertising for good reason: they are the easiest thing to fabricate and the hardest thing to verify.
Every item above is answered directly on this site, not asserted: verification, recourse, and the legal claim path.