My young friend went on contract for a year, doing fishery research. After a few months they said "We aren't going to pay you any more. You can't leave because the boat won't come back until {whenever}. And if you say anything, we won't give you the recommendation you need as a young researcher doing a PhD."
She had to stay for months working for nothing. It's slavery, and they know it, and that's how it works.
My young friend went on contract for a year, doing fishery research. After a few months they said "We aren't going to pay you any more. You can't leave because the boat won't come back until {whenever}. And if you say anything, we won't give you the recommendation you need as a young researcher doing a PhD."
She had to stay for months working for nothing. It's slavery, and they know it, and that's how it works.
Don't go.