If you've activated a subscription after 14/9/2016, and before 10/7/2017, the below will happen.
The calling minutes, text messages and mobile data limits in your bundle are valid for one month only. You can only recuperate your remaining calling minutes, because they'll be converted into extra mobile data automatically at the beginning of each month.
Your texts and mobile data do not carry over to the following month. Each month, you pay for a new bundle of calling minutes, text messages and mobile data.
If you've activated a new subscription after 10/7/2017, or updated your old subscription after that date, your unused calling minutes will not be transferred to mobile data.
You'll find these dates relating to your subscription at the bottom of this page in My Viking (SIM History).