Was I wrongfully demoted? Is my new pay fair?

I have been employed at a company for almost three years (for my protection, i do not want to disclose the company). I was promoted to a supervisor position about a year ago. In January, i transferred locations from one state to another, with the knowledge that my pay would decrease due to cost of living.

Last month, during another transfer to a different store within the district I was told by the store manager that my position as a shift was not correct. i should have been demoted before arriving to the original transferred store. As a result, I lost my position and pay. I was not warned about this demotion or pay, and no action was given to me to try to resolve this. I was told I had to retrain and try gaining the position again.

My current pay is less than that of a starting employee for the company. According to the district manager, the pay reflects what I would be at had i never been promoted from my current state.

Is there something I can do to fight this? I have been with the company for almost three years, I did not request the demotion, and I have suffered extremely from this financially. I will unable to afford living expenses by the end of the month, and I have had no luck in being helped from management to compensate a rate of pay that would reflect the four raises I received before my promotion.

What should I do? My current pay is $2 less than I was making, and my hours have been cut in half.

I would also like to add that I had been transferred originally as a shift for FOUR months. It was only after a conversation between each store's managers that I received a call that the demotion and pay cut was occurring.