Perhaps not, but that doesn't mean it's not paid for. And in any case, I'm sure the terms would have been different in different cases, and it probably was poss

Perhaps not, but that doesn't mean it's not paid for. And in any case, I'm sure the terms would have been different in different cases, and it probably was possible to quit if you were able to pay for your previously-rendered services in some other fashion. Of course, these are just details. Fundamentally, those indentured were held captive and forced to work. But that still doesn't make it unpaid, or involuntary for that matter. The bondage existed only to enforce the terms previously agreed to. I have no way to know, but I imagine many indentured servants were happy with the trade, though many also weren't. Lots of fraud too, with people being tricked into it. As I write, I can't help but think of student loans which have similar characteristics.