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