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