Hello drowned
Sorry to hear of the billing confusion fallowing your disconnection request, we appreciate you taking the time to raise this via the forums.
As with all customers, we continue to bill customers up until the date the disconnection of service is completed. At that time, a final bill will be produced which will take into account any funds taken or raised via the previous bill.
If any funds are taken via Direct Debit, these are returned via cheque within 35 days of the disconnection or a revised final bill to cover the services up until the disconnection. We wouldn't recommend cancelling your Direct Debit as any missed payments can lead to adverse information being recorded against your credit file.