korea employment visa teaching jobs Korea notice period korea work visa status Saramin part-time jobs Korea Korea job search guide work visa korea XpatJobs visa sponsorship Korea KOTRA job fair Kowork jobs in Korea for foreigners Seoul Global Center freelance jobs Korea fired in Korea visa quitting job Korea foreigner JobKorea employer shutdown foreign worker Korea LinkedIn Korea work visa korea rules job termination Korea foreigner work in South Korea 2025 unpaid salary Korea foreigner foreign worker job change expat career Korea English jobs Korea foreign worker resignation change job korea visa employer no response Korea non-teaching jobs Korea company closed Korea visa foreign worker ghosted Korea Korea job platforms foreigner jobs Seoul resigning job korea