Changing rate of pay

[baybay]

I was on salary with an organization when the new owner took possession. For 5 weeks, I worked 5 days a week but over 40 hours per week and was paid my weekly salary. In other words, I was paid my daily rate for 5 days work regardless of how many hours I worked. I was then cut back to 2 days per week (I only worked 4 hours per day) and was paid my daily rate for the first pay period. The employer then decided that I was to be paid hourly instead of the the daily rate without discussing it with me or notifying me in any way. He is now wanting to go back to the 2 days for which I have already been paid and pay me an hourly rate to recalculate the amount and to say that I owe him money. If he is going to go back and do this, should he not have to go back to when he took over ownership and pay me the hourly rate from that period including the overtime that is due? Sorry, this is in the state of Alabama.