Up aginst a rock and a hard place

I'm English teacher in Yeongju in the very rural Gyeongbuk province. I don't have an understanding of Korean law, but I think my public English Center is doing some pretty shifty things. So I'm just writing to relieve stress and maybe get some help understanding an clarifying if what's been happening gives me . I'm beyond my cause to formally complain.... I have called every office of ministry to ask for help and they keep telling me I should ask elsewhere. 'I'm pretty much at wits end and I just want to get out of this nightmare -fairly. I know that rural schools are let off the hook alto because of their status, but they take small town politics to a new level.
1. Many teachers are hired and work for months without visas. These teachers are paid through other teachers accounts
2. The school often obligates us to work overtime without extra pay.
3. School obligates us to work extra English camps during vacation time. We are paid extra- however the rate of pay is changed drastically and without warning. usually after the camps are over
4. The school obligates teachers to attend impromptu dinners and noraebangs after school hours which last 6-8 hours.
5. School principal openly sexually harasses and man handles female teachers while drunk at said dinners and noraebangs.
6. The school does not recognize the contractual 15 paid sick days in our contracts. Teachers are hassled while sick and forced to come in anyways.
7. I am eligible for a pay grade for a EPIK GET level 2. However I was threatened into signing a contract that says GET 3. After many discussions- my pay grade level went up to level 2. However the contract says level 3. I've complained but was told it's a non issue. Now( after 10 months) the school is claiming overpayment: they are lowering my salary and taking my severance pay to compensate.
8. I requested a meeting with my school board where I discussed concerns about contracts, teaching hours, and teachers health. Afterwards, I actually ended up in the hospital for 4 days. Due to this I am being asked to non resign at my school. However it's been our understanding that i would resign since January; therefore I am not prepared for a move or another job search.
9. I've requested meeting with my principal and City board of Education- however, they are friends and are both refusing a face to face meeting, refusing all calls, and not responding to emails.
10.My principal wants me to write a letter stating that I don't want to resign. When I refused I was threatened with a poor reference and possible black listing for my particular town.
11. Our school is a center that operates with 8 teachers. We are losing 4 teachers in one month. There are no other teachers to take our spots. 2 of the teachers happen to be Caucasian and they have been written and formally asked to resign, however myself and the only other African American teacher want to resign and are being rejected. My co teacher informs me that the principal would like more Caucasian teachers for better image.
12. I secured a new job to go to .. however my principal called and got my offer withdrawn.