Insisting on debiting premiums on wrong date.

I just received a letter from MiWay informing that my policy has been canceled. However they have been trying to debit my account on the wrong date repeatedly even after explaining to them that changing the debit order date will lead to non payment because I only use that account for debit orders. If they try to debit on different day there will be no money in that account. However they still continued trying to debit on a date of their choice. An option that would have worked is providing me with banking details so that I can make direct transfers in the case of a missed debit order. Another work colleague was complaining of the same thing. I was called by a consultant and informed that it will be escalated but no one called back. Since 2014 with two insurance companies I have only claimed once for roadside assistance after my battery went flat.