Pathetic and Unfair Customer Service

I have been sitting with this same problem for the last 3 months going onto 4 now. My debit order was always scheduled for the 15th of every month due to this being the day I received my salary. I started a new job and now get paid end of the month. I have spoken to 3 diffrent consultants each month to change my debit order to month end. Each one promises me yes it is changed. Every month same story the debit order goes off on the 15th. Low and behold last month they switch off my phone (After speaking to consultants twice) They then procees to force me to pay that months bill before my phone gets turnes on. This inconvenienced me tremendously financely. I have to suffer due to their fault!! After sorting it out, I get promised yes your debit order has been changed to month end. Can you guess?? It went off on the 15th again this month!! I am sick and tired of this!