Poor service and change of debit dates without the approval of clients

I have experience bad service from MFC since December 2024, 1st they debited my account earlier than the normal debit day and made a doubt debit which made affected my account so badly because other debit orders we bouncing back due to insufficient funds. I made a call to reverse the money which in the end it was reversed few days later. Again this January as soon as there were funds in my account MFC made an early debit without my approval and made a double debit which is taking me back to having accumulating arrears and impacting badly on my credit score. When you try to reach out to them you always encounter these rude consultants who are unable to assist you and they will always take you from piller to post.