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