Last december I subscribed for the promo, that you pay for one year for the price of ten months. It expires on december 24. If I switch to Premium Family now, will there be a compensation with the price for the Family subscription or a refund? Otherwise I would not have saved anything thanks to the year promo.
When you change plans, your new subscription will take effect at that time. Since you already paid a full year for Premium any remaining balance will be applied to the Family rate the date you start it. You will likely see your renewal date move forward from December as well since the plan is an increase in cost. I hope this helps answer your question and have a fantastic day! 🙂