From the list of devices (at the top), select the mobile number the limit should be applied to.
From the left menu, click Limits & Controls to expand.
Click Limit data.
Click No limit to uncheck the box.
From the GB per month field, enter the data limit.
Once the limit is reached, data usage is restricted until the next billing cycle.
You and your child receive free text alerts when they've used 50%, 75% and 90% of the limit.
Select one of the following:
Selected when a dot is present.
Allow data use when limit is reached, but still notify me.
Block data use when limit is reached, but still notify me.