Hi DanielS (or any BT bod)
I have a similar issue to the original poster. It looks like I have been still paying for an account that I closed over four years ago. Also in that period (having assumed the original one was closed) I signed up for BT Sport again to go with a SKY subscription. This was then closed last year.
So for a period BT were taking two direct debits out each month, one that I knew about and the old (assumed) closed legacy one.
Is there anyone I can speak to about this?
This all came to light today as I have just signed up to a new BT Broadband account.