Buy credit and auto top up
In my software, I allow customers to buy credit for making and taking phone calls. I want to let my customers define a threshold that if their credit balance goes below it, their card on file will automatically be charged to buy a new credit pack.
I manage the phone credit on my side and I need a way to charge the card without user presence when I trigger it - so it's kind of like a recurring payment, but it's not scheduled. How do I go about doing that in Zuora?