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