Incorrect debit order date

I have a debit order dated for the 20th of each month. This is the second time the debit order went off before that date leaving my bank account in a minus. This is unacceptable as they are messing with my credit record. Other institutions send you a courtesy sms to remind you that's your debit order date falls on a Sunday and that you should ensure funds available the next working day. How can you (Miway) deduct money before the date your clients agree to? I have to carry bank charges due to you not adhering to our agreement, this is extremely upsetting to me as I am incurring extra charges because of you. I have been a loyal customers and not once was a debit order ever returned due to insufficient funds. I am really ****ed off as a persons credit record takes a while to update and this will show on my risk grading at the bank for a whole year.