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