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