Debit order drawn on the wrong date. Nobody responds to queries.

For the last 5 months have asked my personal banker as well as the personal loan department to update the date they have the debit order for that account since I'm paid on the very last day of the month. Every month on the 25th the money is simply transferred from my cheque account. This month I'm overdrawn and I'm getting a snotty message to say ... FIX YOUR OVERDRAWN ACCT now. And account that WON'T be overdrawn if the bank can get their processes sorted. WHY do I have a personal banker who can't help. Why is it so difficult to get the loans department to get their act in order. So now their processes are costing me more money to pay for this overdrawn transaction. Getting my personal banker to phone me is impossible. I sent a message in JULY. IT's not the end of November.