If you run out of an allowance, you can still keep using it (for example, if you run out of texts you can keep sending text messages), but you'll be charged at out of bundle rates. These can be quite high, which is why we give you the option of buying add-ons of minutes, texts and data.
Buying an add-on will prevent you from racking up additional out of bundle charges. Add-ons last 30 days, so if you're running low on any of your allowances - or if you've already run out - it could be worth investing in one.
Please note: add-ons can't be backdated to cover your past usage. They come into effect when they're purchased, and never before.