Absolutely! If you need more minutes, texts or data you can always add Top Ups. There are no limits for how many time you can add a Top Up or any extra fees. Top Ups are eligible for rollover, as described here.
To add a Top Up sign in to your dashboard, select the line you’d like to add Top Ups to and click on “Add More”. Select how many minutes, how many text messages, or how much data you want to add, and buy it. They will be ready to use soon.