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