Taxaroo give you the option of purchasing credits for enhanced KBA or minutes for video calling. You can select an option from the drop down in the products field.
How to Purchase Credits
Step 1: Go to https://app.taxaroo.com/login and login to your account
Step 2: Select the down arrow on the top right hand corner of your screen and select credit dashboard
Step 3: From this screen select the purchase credit button
Step 4: Select the drop arrow and choose what you would like to purchase and check the box to confirm. When finished make sure to click purchase.