Can an employer change your wage every time he desides he wants to like take you off your pay and change it to piece work, and than change it to a forced sub contractor and say your making too much money so now you can no longer be a sub and put you back on hourly

Assuming you are in the US,

A employer can change their employees pay anytime they want unless there is a labor agreement ( union contract) or a employee contract.

They may decide not to use hourly or salary employees and go to contractors ( you are not forced, you can go somewhere else to work, you are only given the first option at being a contractor)

I wonder if you work for the company I work for, we have had our pay changed about 6 times in the past 4 years, from contractor to commission, to salary to salary plus commission to bonus system.

But yes, if you are not happy with it, you leave and go to work somewhere else, if they can't keep any workers, they end up finding a better pay method

It doesn't sound legal or ethical to me. Contact the Labor Relations Board with the specifics.