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