UNAUTHORIZED DEBIT ORDER DATE CHANGED

I am so angry and am actually going to take this up to the Ombudsman. This is ridiculous that I receive a sms telling me my debit order will be changed an debited on the 15th of December?? Like really who the hell gives you the authority to do so?? without asking me or even getting my authorization. This is against the law. I signed a contract for my payment date now I am told they going to change it?? Is Direct Axis paying me on the 15th that they decide they going to change it?? this is un lawful.