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