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