Payment handling
How the add-on amount is collected depends on how the original order was paid. The plugin always resolves this from the order's own payment, not from anything the customer changes afterwards.
Invoice, prepayment, cash on delivery, direct debit
While the order is still unpaid, the add-on amount is simply added to the order total. The customer pays the new total the same way they were always going to. Nothing else is needed.
If such an order has already been marked paid, there is no open balance to add to, so no offer is made for it.
PayPal (with SwagPayPal)
PayPal here means the PayPal wallet method. There are two ways the add-on is collected, and the plugin picks automatically:
- Silent vault re-charge (best): if the customer has a saved (vaulted) PayPal payment, the add-on amount is charged in the background before the item is added: no second PayPal step.
- Second approval (safety net): if they have no saved payment and you have enabled PayPal: collect upsell via a second approval, the customer is sent to PayPal once more to approve just the add-on amount. After they approve, the item is added. If they cancel, nothing is added and nothing is charged.
The add-on charge is recorded as its own PayPal transaction, so the order shows the original payment plus the add-on, and you can refund either one from the order's PayPal tab. Full setup is in PayPal setup.
The second approval is only for customers without a saved payment. If a vaulted customer's silent charge is declined, the add-on is not added: there is no second-approval fallback in that case. PayPal's own card method (ACDC) is intentionally not eligible.
Cards and other providers
Credit/debit cards and other providers (for example Stripe, Mollie, Klarna, Adyen) are not charged again automatically in this version. Either restrict such campaigns to the supported payment methods, or do not offer on those orders. (The campaign's Allowed payment methods picker already lists only the methods the upsell can apply on.)