Best answer by Mohammed
So the text you get applies to your inclusive data.
Let's say you had 1GB on your plan.
Once you've used up 800MB, you'll get a text saying 80% of your data allowance has been reached.
Once you've used up 1GB, you'll get a text saying 100% of your data allowance has been reached.
texts are subject to coverage and are not guaranteed.
If you purchase an add-on when you still have remaining data, your inclusive data would be used up first and then your add-on.
This can lead to a text being sent when you've used up your data (but you know you had an add-on active.
The correct allowance will be what shows on the app.
Have you had any recent charges applied?
EDIT: Moved to the section: Bills, allowances, charges & capping