Yes @cyber Vodafone bill in advance and you would have effectively paid for the final month. When you leave you will receive two final bills, one should have a credit and the final 0.00 bill as your confirmation the account is closed with nothing further owing. Vodafone recommend keeping the direct debit open until the final bill has been received when it will be automatically cancelled.
See things to know before you leave here: Cancel Account and the support link Final Bill
