There are some films that are so bad they're good, some that are overall bad but are worth watching for some interesting concepts brought up or other redeeming qualities - but I just don't recommend watching this one at all. It would be more valuable to take the premise and write something yourself, as that might be at least a little more interesting (and original).
As others have stated, there are many directions this film could have gone, and nearly all of them might have been better.
The premise quite nicely allows for intrigue and horror aspects throughout, but the climax and resolution which that world leads up to are simply disappointing (and gross).
The characters are two-dimensional and mostly either bland, forgettable or unbearable (or perhaps both, unbearable in their blandness). Not to mention completely unrealistic. Motives are not clear, or legitimate motives are not present throughout. On top of this, motives are blurred even more by stupid plot-twists.
Many loose ends, ideas abandoned within minutes of their introduction, never to be brought up again.
There is nothing new here - we've got trope-filled exploitation, unlit torture rooms*, hardened victimised prostitute girls, some tacky and pointless gore, insects in stomachs**, and, drum-roll... a cheap resolution backed by cheesy pop-style music. Leaves a bad taste in your mouth and completely devalues the rest of the movie (assuming it had anything of value).
As for a PSA about human trafficking
it almost seems insulting. In fact, as mentioned in the credits themselves, there are thousands of cases of human trafficking per year - it seems insensitive to dramatize the issue unrealistically, and then pointless to watch this unrealistic movie about it when it's already happening on such a large (considering) and terrible scale.
*Which at first I questioned... Sure, it's atmospheric, but I feel being trapped in a constantly brightly-lit place would be terrible too, mess with your circadian rhythm in a terrible way. I realised it's most likely because bringing in electricians raises your risk of being caught.
**Not sure what's with this theme in horror - bugs are friends.
