Maybe these people were probably offered a different job at first, but when they got to the actual work, it turned out to be a scam. They probably can’t leave anymore because there’s a big syndicate behind it. The pattern seems familiar, kind of like the scenario with POGO here in the Philippines.
I call this deceit and exploitation, and another one is what the Chinese are employing to their fellow Chinese, giving them loan after their potential victims lose a lot of money from gambling. They offer the victim huge loan and with exorbitant interest if the victim cannot pay anymore, they kidnap them and forcibly work them on POGO.
That's the stories of many Chinese who became victims of POGO, so people should get familiar or check the background of those offering too good to be true jobs or investment its likely a scam and you will regret later.