student visa document mistake Korea d-10 visa korea part-time work Korea international students student visa korea attendance rules Korean university visa hikorea d10 student visa after graduation student part time work korea visa part-time work Korea job seeking visa korea university change immigration Korea international student visa rejection Korea student visa Korea student visa instability Korea international student Korea D-2 visa Korea international student attendance Korea international student administrative risk Korea D-4 work permission study in Korea student work permit Korea student visa pattern issues Korea student visa transfer Korea student attendance Korea student visa attendance rules Korea international student immigration review Korea D-2 part-time job international student job rules korea student visa korea rules international student korea immigration attendance korea student visa korea attendance work rules international student korea immigration international student visa korea problems