Pathetic and worst service ever!!!

I have requested to change my debit order to the last day of the month as I have changed jobs and have been struggling with this. Your consualtant keep sending me from pillar to post, promising to communicate feedback and nothing has happened. I spoke to Sibongile on Wednesday, who promised to call me back the following day and never did. She promised to copy me on the email with respect to my query and that was never done as well. Clearly I am being taken for a ride and a fool. This is the most pathetic service I have ever received from BMW. How difficult can it be to change a debit date??? I will fight you to the teeth if this is not done and and the debit goes off on the 20th as that will affect my bank account and credit history. Surely your consultants knows nothing about customer service. Pathetic and worst service!