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