You can reach out to our supportive Customer Care Team at 03301188871 (choose Option 5 on the IVR) from Monday to Friday between 9 am and 5 pm, and on Saturdays from 9 am to 1 pm. Alternatively, you can email us at support@v4consumer.co.uk.
For more: https://www.v4consumer.co.uk/how-can-i-change-my-direct-debit-details-before-my-installation