Change of Bank details

For the past 3 months i have been trying to change my bank details with momentum with no luck.<br> I have sent numerous emails to them requesting the change along with all required documentation they have requested. <br> Still every month they debit the wrong account incurring additional bank charges for myself claiming that they have received no documents from me.<br> It really is a classic case of a company growing to big and not being able to manage their clients correctly.<br> On numerous occasions i have told them i am prepared to cancel all of my policies if they can't change my details and it doesn't seem to bother them.<br> What kind of company doesn't care about your business or how big do you have to be to not care about losing clients over something so ridiculous. Just because they are unable to change bank details.