poor accounts management

I supp**** the insurance with my new banking details and they in turn assured me they have been changed. Now come month end both my accounts have been debited, for the same month. As if that was not enough I receive a letter stating that my insurance has been cancelled! Since this was unfair I went and reversed the second premium since the first have already been deducted. There was no thorough checking on their side, all I have received was an email! This is so appaling. Over and above I have to spend money calling them for the rectification