Libya opens investigation into slave auctions following CNN report
http://edition.cnn.com/2017/11/17/africa/libya-slave-auction-investigation/index.html
Many refugees are exposed to encounter the similar circumstances, especially when they immigrated into other countries illeagally. They can't resist everything as far as they are not protected by local police, because they will be deported to their home countries once they report something to police.
Though I can't come up with the way to remove their risks, United Nations have to think about what to do.