Find "Usage"
Click Vodafone Mobile Broadband.
Click Preferences.
Click Usage.
Select option
Select one of the following options:
Enter usage limit, go to 2a.
Select warning settings, go to 2b.
Enter usage limit, go to 2a.
Select warning settings, go to 2b.

2a - Enter usage limit
Highlight Volume-based.
Highlight the field next to "Limit".
Key in the required amount of data.
Key in the required amount of data.
2b - Select warning settings
Click Warnings.
Click the box next to "Warn before reaching limit" to turn the setting on or off.
Click the box next to "Warn when limit reached or exceeded" to turn the setting on or off.
Exit
Click OK to save the settings.