You are acting like the case is that the girl was kidnapped or taken from their family against their will. Barring extraordinary circumstances, this is far from the truth here. More likely than not, this is the case of some poor family that couldn't take care of the girl and gave her away.

It is a horrible arrangement, and she should be given a lot more than what she is getting (at the very least, she should be given backpay + pension equivalent to the market rate of her work for all these years), but to treat this case as some sadistic family keeping someone in captivity is overreacting.

maybe.. but it's very close to "sadistic family". It's very very close. It wasn't slavery, but excruciating close to slavery.

And definitely the punishment given is a complete under-reaction and your attempt here to lighten the situation lightens it way too much.