Is it legal to hire a RN at one wage but pay minimum wage for state mandatory orientation?

I am a nurse who has moved back to MI from FL after 38 years and one raised family later. I was hired a month ago by a home care agency that accepts medicaid insurance almost exclusively; therefore greatly lowering the hourly wage (several $ an hour). Employees as in any healthcare situation are required to attend inservices and company education and policy updates and meetings. I was informed after 10 hrs. of mandatory office hours that I would only be paid min. wage for any mandatory office hours. Pay checks are weekly yet I was not paid on the pay date and can’t get a straight answer as to when my pay will come. Also , I was informed that I wauld go to work after this “orientation” but over a month later I am still waiting for a call to work. I am experienced with infants and children on ventelators and was told this would be my assignment. I proved my competency via demonstration and written test to the company as is required per policy.