How can an individual or even a group of individuals stop a corporation from underpaying its workers so that they need to use some public assistance, food, or medical care?
There are many similar examples, but they all boil down to the asymmetry of power. An organization capable of employing many lawyers, or even a single good one, can grind you down until you have nothing left. I still see libertarians as having no answer.
I think the only way to fight back against corporate abuse is to build a stronger center of power. Something like a union, a citizenry willing to take collective action, or even a Government that is not beholden to corporate interests.