Debit Order

I spoke to a consultant at the call centre just before the end of March as I wanted to load a debit order to avoid the hassles of making manual payments monthly, as it was too close to the end of the month I was advised that the debit order would only go off at the beginning of May and that I would have to make a manual payment for April which I did. Today I decided to call the contact centre as no debit order went off my account and was then told that unfortunately my banking details were not verified and I would have to make a manual payment again this month. How is this possible after spending 15 minutes on the phone previously confirming all my details and the consultant said everything was in order. Furthermore I get told that I must call back at the end of this month just to check if the debit order will go off in June as if it does not then I must make a manual payment again. What is the purpose of having a debit order option if you cannot make use of it? Service is pathetic. My customer account number is ***0. Sort this out.