My question involves employment and labor law for the state of: KY

I recently switched from a full time hourly with benefits position to a PRN (as needed) position in the healthcare field. The specific position is new to the organization. Before making this switch, I found out as much about the position as possible to help make a better decision, attemping to calculate all risks. This is what I learned:

* I am required to work 3 out of 4 weekends (sat. and sun.)
* My hours are not guaranteed.
* I will be compensated X rate on the weekend.
* If I work during the week, I will be paid at rate Y.
* Rate Y was verified by a written document, stating that anyone who works during the week will be paid at rate Y rather than rate X.
* Further, a human resources officer as well as the director of my unit stated that I would be paid rate Y on the weekdays.

The problem:
A week and a half into the position, an email is sent out that a mistake was made and we are actually going to get paid a new rate on the weekdays considerably less than rate Y. When further information was requested, we were told it was a "miscommunication" and chopped it up to human error. An apology is all that was offered. This may have been a "miscommunication" but it was miscommunicated the same way from various written and verbal sources. I believe the organization should honor original rate Y since that is what was promised when I made the change. It is what I was promised when I signed my change of status form.

Can anyone shed some legal light on this situation, please?
Thank you.