Changing debit order date

Trying to change a debit order date from the 25th to the 1st of the month or last day every month. NO feedback and empty promises. They are unable to change the debit order via telephone you need to complete a form requesting changes. Employees at academy of york keep telling me they will send this form to complete but I am still waiting and paying penalties every month. HORRIFIC SERVICE!!! The call centre agents are rude and unhelpful basically accusing you of lying about requesting these changes numerous times before.