immigration overstay decision Korea korea travel tips Korea tax refund night transportation Korea VAT refund Korea taxi at night Korea korea sim card Tax refund in Korea missed last subway Korea korea tourism guide tourist overstay Korea consequences 한국 세금 환급 late night bus Korea Myeongdong tax kiosk travel to korea 공항 환급 방법 korea mobile internet k-eta korea visa free korea korea connectivity esim korea 외국인 택스 리펀 korea entry requirements 서울 쇼핑 환급