By living in Korea, do you mean your a resident there and can provide proof of residency documents? If you're not then you'll have issues applying through that website.
Even if that statistic were true which I doubt it is, he probably just made it up out of thin air, all it would mean is that the only people suspicious enough to hire a private investigator turn out to be the ones that are being scammed, which is what you'd expect lol
Would like an empty SIM card. I know some third party places that sell them for like ฿40 in the city, just wondering if anyone knows if you can get one at the airport.
If it's just a tourist visa or exemption then just go yourself. It only makes sense to use an agent for more complex tasks, you'd just be unnecessarily inserting a middle man and wasting your money. Good luck.