This certainly seems to be a bigger problem than I am sure most of us realised.
It is reported these unfortunate people are kept under control by threats and intimidation regarding the family they have left behind in there homeland so is the term slavery for all really accurate or are some more like indentured servants.
In this day and age I think both are wrong.
http://www.differencebetween.net/miscellaneous/culture-miscellaneous/difference-between-slaves-and-indentured-servants/