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