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