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