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