Incorrectly debited

I called the customer service department because I need to change my banking details and the consultant updated it for me. But month end when my debit order went off I was debited more than usual. When I called them again I was transferred from pillar to post afterwards was advised that I called in and subscribed to call minutes, but I did not subscribe to call minutes I only called in to change my banking details. The consultant advised she will escalate it to her team leader because I requested for a refund. She also promised that her team leader will call me in the next 24hours and I never received a call. I requested a reference number and was told there is no reference number. Since when does a call center not give a reference number? Why did I not receive feedback?