I wanted to sort out a missed debit order and wanted to find out why my debit order date was shifted from 25th to 15th

I wanted to sort out a missed debit order and wanted to find out why my debit order date was shifted from 25th to 15th. The call centre agent said it could be changed but would only take effect in the next month, not in the current month. I emailed Netstar and they put it into effect immediately.