To log in to My Vodafone you need an email and password.
You can change your data tariff there. However, if it's an integral part of your tariff (e.g. in the Red Full tariffs), it is not possible to change only the data tariff, you will have to change the whole tariff solution.
Connection for a month is a good solution for undemanding users who use the Internet only occasionally.
This message is sent as soon as your mobile phone connects itself to the Internet. This can happen without your doing, for example during an update of a part of the system or a mobile application.
Are you not aware of being connected to the Internet?
If you have a smartphone (such as Android, iPhone or Windows Phone) and you also send MMS, we recommend having any data tariff active and allowing data connection on your device. If you block the data connection, you might not be able to send MMS (we do not charge data used by receiving/sending MMS).