Tea plantations in Assam pay starvation wages, and claim they "can't afford" to pay more.

Of course they can afford it. They simply have to raise the price. That's fine — we can pay a little more for our tea.

The poverty of the workers pushes them to fall prey to selling their children to be domestic slaves. This is a separate problem, and could be tackled by informing people around India about the dishonesty of these recruiters/purchasers.