You're familiar with voice phishing, aren't you? Specially if you're living in Korea, this words or tactics on how to make money through deceiving others is very popular in Korea. The most popular one is the Post Office Voice Phishing. They call and tell that the caller is from the Post office and will tell you to send some money or you need to pay some amount of money. It's easy for Koreans to be deceived because you can do lots of things in the post office. You can send money, pay bills, pay insurance, taxes, etc. So, if you use some of their services, you would believe if someone call you and tell that it's from the post office and you need to pay some amount of money.
Just a few minutes ago when I received a phone call. It appeared on my cellphone that it's an international phone call so when I answered it says "Annyeonghaseyo, ucheguk imnida..." so I suddenly hang up. I was so irritated. They are smart enough to use international phone call as a caller. I'm 100% sure that it was voice phishing. There aren't many thieves in Korea but there many deceivers and they do it secretly.