What legal a actions should I take if my boss tells me that my check is going to be three days short?

So I have worked for this daycare for a little over a year now. Every since I started working there I have always gotten paid with a written out check. About a two weeks ago the owner of the daycare tells me that they have switched banks and that my check will be direct deposited into my bank account he also stated that they will not be writing out anymore checks. I wasn't given much information on the change at the time and when questions were asked he said that he would talk details with me at a later time. Now this week he tells me that my check is going to be three days short because he had to cut the checks off on Sunday instead of Wednesday in order for me to keep my original pay date. I never signed anything saying that was OK with this decision and he is saying that this decision is final and I have also tried reach out to him about it a couple of time and still no results. I don't know where to go from here so I would love if someone could give me some a advice.