To ensure you are always aware and in control of your data consumption:
While you are on a data pack - You will receive SMS alerts at 50%, 90% and and at 100% of your usage quota
While you are on standard PayGo rates - You will receive SMS alerts at every 25MB usage.
There are also multiple Self-Help options for you to check your internet usage:
Visit the My Vodafone App and check the usage details.Download here
Send an SMS "DATA BAL" to 199