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