Since payouts by Billie to the merchant are made immediately after shipment of goods or delivery of the agreed service, customers need to pay back their invoices directly to Billie upon the due date. Therefore, Billie is using so-called virtual IBANs (VIBANs). VIBANs are delivered back to the merchant in response to an (accepted) order creation request. VIBANs are unique for each of your debtor/customers. The VIBAN needs to be put on the invoice which the customer receives for the purchase.