So it turns out that the enslaved Oompa-Loompas in Willy Wonka's chocolate factory were just truth in advertising. There's quite a bit of irony to that particular controversy.
For those who don't get OP's reference, in the original version of the book, Oompa-Loompas were literal slaves form Africa. The publisher made Roald Dahl change them to mythical creatures.
I can find a lot of stuff written online about this, but none of it quotes the original text.
The original oompa-loompas were pygmies from Africa, written in a pretty racist way, and with wonka being a type of white-messiah-savior for them. I can definitely see an argument that wonka was a shitty employer, violating all sorts of legal and moral rules. But we're they actual slaves? From what I have been able to find they were paid, but chose to take payments in cocoa. Were they forced to work and imprisoned?
I guess I would like to see the original text, as all the articles written on the subject make proclamations of them being actual slaves, but don't show anything from the original text (or make the argument) to demonstrate they were actually slaves.
One such article: https://historynewsnetwork.org/article/170755