When you sign up for a service paying with your Credit/Debit Card, it's set to automatically renew on the due date by taking payment from the card details stored in your Customer Portal account.
If you would rather this not happen please email the billing team to have that service changed to either BACS (Bank Transfer) or Cheque payment, you need to request this per service as it is not an account wide setting.
Once set to BACS (Bank Transfer) or Cheque you can still pay by your Credit/Debit Card manually, it just means we will not automatically bill you.