The Maid's pay in the US should not even be a issue as per the Vienna convention.
Article 47 of the Vienna convention on consular relationship states clearly that the domestic staff working in consulates do not even require a Work Permit, thus excepting them from the labor laws of the host nations. Also the minimum wage laws of the host nation.
As long as the minimum wage law and labor laws of India was satisfied, there is NO legal case.
There are staff in the embassies and consulates of MANY nations in the US who do not get minimum wage as per US laws. Ever wonder why the US state dept or NY DA never crack down on them ?