Is it possible to find a good academy for foreigners in Gangnam?

Hello! It's been about a year since I came to Korea, and I am working as an academy instructor in Gangnam. I recently started working at a well-known academy chain, and I want to share some strange experiences I've had here. I felt uneasy from the beginning, and it seems my suspicions were correct. For example, all the training in the first week was conducted online. Even though I didn't pass the training, they still assigned me classes right away. When I asked the manager for help, they just told me to figure it out on my own, and later scolded me for not doing it properly... I also didn't receive the airplane fare that was supposed to be included in my first paycheck. It was stated in the contract that it was included in the first salary, but the manager said they would give it to me later along with severance pay. The contract states that I have to work for 364 days, so I'm worried if I will even receive it properly. Recently, I asked how to apply for vacation for a family funeral, and the manager told me to take a day off on "a red day or April 31st." But April 31st doesn't exist. It was really awkward. I'm wondering how to handle this situation. Does anyone have a similar experience? If anyone has advice on good academies or how to deal with this situation, I would really appreciate it!