MFC Breach of Contract

I have a contract with MFC for vehicle finance, Have never missed a payment or been late. Every month the debit order goes of like clockwork. My contract with MFC states the debit order is due on the 1st of the month. Lately MFC have taken it apon themselves to take the money sooner.

When I phoned them to enquire about this, im told that an SMS was sent out informing me that they running a some or other program to match my salary date. So they basically decide to take the money and if you dont respond to the SMS that take that as an OK! Contractually we have agreed on the debit order running on the 1st of the month. CONTRACTUALLY! Who gives you the right to take the money sooner. Why not send a message stating that "we would like to move your debit to this date, If you agree please reply with YES. If no reply we will carry on as normal"?

You are in breach of conrtact and if you take the money out my account one more time before the due date I will make sure there is no money in that account for you to take and i will also report you to the ombudsman.

Are you hard up for cash that you must take money early to pay your salaries or what?