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