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