I have a 70 GB data bundle, and still I have to pay for data. Why?
Have you recently been abroad, or are you still? This is why: up to 27 GB there are no extra costs for using data in the EU. If you use more, every used MB will be charged at € 0,002/MB.
Outside the EU, the normal roaming rates apply, and you can’t use your 70 GB data bundle.