Also, if you are a classified as a contractor, check and see if you fit the legal profile of a contracdtor. Just because a company hires as a contractor does not mean the law considers you a contractor. And whatever the law states overides anything else.
Even though the employer said he would only require you to work 5 days, he has the right to change his mind. Needs of the business will be his defence. He hired you to work 5 days but because you dont work under an agreement that requires them to give you any notice, or just says they cant change their mind, the company has done no wrong doing by changing your schedule as long as they compensate you correctly