When a customer owes more, they get a payment link and the order stays on hold until it’s paid; the app lists unpaid orders for you to follow up.
When the total goes down, the refund goes back on its own, to the original payment or as store credit, or waits for you to approve it, as you choose in Settings.
Still stuck?
Open the app in your Shopify admin, go to Help and click Chat with us, or email [email protected] with your store’s myshopify.com address.