hello Madam, here is my view:

How much was their salary? Satisfying housemaid is not by salary, just make her happy like your blood and you get the best of her.[b][/b]
How do you balance being nice and not give too much liberty. [i]Be discipline and sincere in your dealings. Let your yes be yes and no remain no. Let no one intimidate or harass her either from within or outside.
[/i]What security measures can one put in place for my kids safety? Get to know her source deeply. Let one or two known people guaranty her.
Did you pay their salary to them , agents or parents?[/color] I will suggest you ask the young girl personally, she is 17 according to your statement, she is old enough to know who should keep her money.

Above all, take good care of your housemaid and she would do same to your household. BE PRAYERFUL AND TRUST ONLY IN GOD.

What is the proof?