Incorrect debit order date

The company debited my account on the wrong date, the debit order was unpaid. Now I am being told that my car is not insured, who's fault is that? I had an agreement with them to be debited on the 20th which was on a Sunday, which is also my salary date. They called me to ask to put through the debit order tonight but nothing. I have never had any bad experiences with but this is the worst service ever. They also want me to pay the admin fee, as the debit order was unpaid but AGain its not my fault. As they did not honour our agreement.