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