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