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