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