Not happy

I keep receiving letter that my policy will lapse as I have not been paying my premiums. Surprising enough, all my policy payments are done via debit order, and I have never missed my payments yet one still gets letters saying that premiums will lapse. It's so annoying that I always take my own time and airtime to be calling the Call centres to ask what's going on and why do I keep receiving these letters. It makes one wonder what is really going on with the accounts department.