1st for Women debiting account on the incorrect date

Debit order set for the 25th of the month. Debit order goes off on the 21st of the month. Phoned call centre to complain and agent says that 1st for Women has access to your bank account and can see when money is available in your account and then they will debit the account irrespective of the date. How is this allowed? People have debit order dates for a reason. Will be cancellaing services with 1st for Women.