Refunds are handled through Shopify when a customer:
Removes a product
Changes to a less expensive variant
Cancels the order
It will send an email and return payment to the original payment method or store credit if applicable. If it were a full refund, the amount is determined by Shopify. If it is a partial refund, Redo determines the amount to refund.
Extra payment is collected when a customer:
Adds a product
Changes to a more expensive variant
Redo will put the order on hold, Shopify will mark the order as "partially paid," and an invoice will be sent to their email. Once that invoice is complete, it will be released from hold and become unfulfilled.
Before going live:
Enable only actions your operations team can support.
Set each action’s window to end before fulfillment starts.
Place a test order and try every enabled action.
Confirm your fulfillment system receives the final version of the order.