While I absolutely agree that this needs to be crackef and every perpetrator personally punished, let's not forget that this is undercover also happening in other countries. Blood farms in India (look it up, horrifying), brick kilns in Pakistan where entire families are enslaved for generations, labour and disappearance camps in China and many forms of illegal slavery even in Europe, America, Australia, ...
Romanians in slave-like conditions on Italian farms, African refugees and economic migrants enslaved in North Africa and Spain, Mexicans and trafficked people in slave conditions across the US, forced prostitution in America, Italy, Germany, Netherlands, Sweden, France, Canada, ... - of locals and foreigners alike. I've heard thanks to the refugee influx you can get a prostitute in Athens for 10€. And all this nightmare is not even counting all the 'arranged marriages' between 12 year old girls and 62 year old 'husbands'.
This is a human problem, and one that far too few resources are spent on. Child abuse gets much attention but factually still too few resources (ask the 9 year old Filipina prostituting herself on Skype - although probably she's still better off than her neighbour trafficked to Thailand). But beyond this, even in what you would consider the most developed countries, you still find slaves. Because neighbours don't notice or care. Because the police is understaffed or doesn't care. Because even when they are saved there are no resources to truly save them.
We all close our eyes and ignore these crimes when they happen in broad daylight. If you are anywhere in a big city ANYWHERE there's a good chance you're not far from a slave. We ignore the rampant poverty that leads to all this. We crack down on 'illegal immigrants' and make legal immigration all but impossible - and push the desperate into the hands of real criminals that then abuse them, e.g. by stuffing them in a sealed container in which they freeze and suffocate to death on their way to their enslavement in the UK.
'Frre the Slaves' estimates that, in absolute numbers, there are more slaves today in the world than at any point in history.
Don't ask me how to resolve this. I just know that somehow we are all complicit.