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