Complex sentence: Others are simply kidnapped and brought into the country when there they are to poor to pay of their transport debts to the smugglers, upon this they are put into what is called forced labor enabling them to pay off their debts.
Split into simpler sentences: Others are simply kidnapped and brought into the country when they are too poor to pay off their transport debts to the smugglers. They are then placed into what is called forced labor enabling them to pay off their debts.