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