Document, document, document each and every instance, date, time, location ... take notes document at home ... whatever they say to you write it down, and ask them to memorialize what they ask, imply, or demand into a written document/email.

CYA... cover your ass,or call your attorney, I always say

They didn't "fire" me, they "let me go". How? It was right around the start of covid. I agreed to resign my current position at the end of February in exchange for a 4 week vacation instead of 2 (so I could visit my family in the US) and a part time position dealing with curriculum, 1-on-1 students, etc., until my baby was born and then after I got off of maternity leave until a new full-time position opened up. Signed the resignation paper and new contract and everything. But then covid hit South Korea, everything shut down, and apparently "the position isn't available anymore" and since the new position hadn't actually started, they were totally in their rights to do that. Until your contract actually starts, both parties can void it for any reason.

I was left jobless and 7 months pregnant at the beginning of covid. Couldn't get maternity pay because you have to have a job to get that. Couldn't get unemployment because you have to prove you are actively seeking employment and at that time it was impossible because... 7 months pregnant and no one would even interview me. It was a mess, but perfectly legal.

As the person below said, document EVERYTHING. If you are in Korea, you can legally record all conversations so long as your voice is heard as well, so record all conversations as well (something I didn't do). And make sure any communication you don't record is in writing. CYA is the best advice <3