Debit order on cancelled account

After having Vox cancel our account a month before they were supposed to, fighting with them for 6 days to reconnect us and only end the account on 31 December, our account has been debited! This comes after having called them on Friday to make sure they have cancelled the account, which alas they had made an error there too! Trying to get hold of anyone in top management is impossible. It’s no wonder there are so many complaints! I sure hope someone will call first thing and sort this out!