Useless service from Marquis

The service at Marquis is just ridiculous. I requested for my banking details to be changed early last year, a simple request that was never processed. I have been having to make direct deposits to them every month which is just an inconvenience. In December they managed to debit from the correct account, however, this month by some mystery they all of a sudden cannot. I called them on Monday to find out what the problem was, they told me my banking details have not been updated and they don’t know why because they have received my bank confirmation letter. The agent promised me that they have update the banking details and that I would get a mandate to my new bank in the next couple of days, tell me why today I’m getting a mandate from the old bank that I no longer use??