You can set any of your SIM cards to automatically refill / top-up when they have consumed all data. This means that your SIM card will always be online. When all data is consumed we'll charge the card you've entered.
Want to ensure that you never run out of data? Configure auto-refill.
Video walkthrough
Steps
Login to the Wave Connect portal
Click SIMs on the left navigation
On the SIM you want to change, click the Refill button and a new window will appear
From this screen you have the option to change your plan by selecting a new option. The selected option appears in blue
Click the Pay button to enter your payment information for the selected plan
Click the Confirm and Pay button to complete the process