korea entry requirements tourist exit record Korea VAT refund Korea tourist medical emergency Korea tourist exit procedures Korea 공항 환급 방법 overstay clearance Korea late night bus Korea hospital visit tourist Korea visa free korea travel to korea 한국 세금 환급 Myeongdong tax kiosk taxi at night Korea overstay exit risk Korea k-eta korea esim korea korea connectivity 서울 쇼핑 환급 korea travel tips Korea tax refund tourist overstay Korea consequences immigration overstay decision Korea 외국인 택스 리펀 Tax refund in Korea korea mobile internet korea tourism guide korea sim card night transportation Korea missed last subway Korea