I selected the wrong base plan and have only realized now that I have used my data allowance. Is it possible to change this mid month without have to pay the total amount again. I hope I only have to pay the balance.
Best answer by Mats
Wait till your base plan is almost up for the 30 days and just buy a data booster in the mean time. Boosters don't expire. Then when your base plan is about to expire buy the base plan that you want. If you change it right now you'll have to pay the full amount.