Why is the amount higher than usual?

It may be due to:
It is your first invoice

The first invoice includes the subscription cost from the day your number was moved over to Trøndermobil until the end of that month, plus the following month

You have called abroad

Calls abroad are not included in the subscription. You can find all prices here (https://www.trøndermobil.no/priser-fra-norge/).

You have used content services

Content services can be TV-guide services, SMS donations or using directory enquiry services such as 1881

You have used your mobile abroad

Use within the EU/EEA is of course always included in all Trøndermobil subscriptions. Outside the EU/EEA there are separate prices. You can find these here

You can always see the details by opening the PDF invoice in your online bank.