Charges a card the customer has already saved. There's no payment form: BillPro charges the card straight away. The card also becomes the order's card.

Set operation to choose what to charge:

• initial_payment: the order's first payment. Use it on an order whose status is draft, pending or rejected. If the order has nothing to collect up front, BillPro checks the card with a 0.00 pre-authorisation and saves it on the order. payment.transaction_type is pa.
• recover_failed_payments: every payment that's due and unpaid. That's each scheduled payment that failed, was rejected, or passed its date without being collected. They're merged into one payment for the total and charged now.

A paid single payment order moves to complete. Other order types move to active.

A declined card returns 200 with result.successful: false, not an error. result.message says why.