The refund engine issues real Stripe refunds and reverses every party — seller commission, brand payout, protocol fee, mission accrual, residual — with balanced reversing ledger entries. Partial refunds reverse exactly that fraction of each party and multiple partials telescope to the cent, with rounding absorbed by the protocol, never taken from a brand, seller, or buyer. Every refund writes an immutable audit trail and notifies each party with the reason.