Cashback will be awarded only on successful purchases, this means that any order that has been cancelled or returned will not be eligible to receive cashback.
If the merchant identifies any of these events, your cashback will not be paid out. If you've already received an instant payout, it will be claimed back or future cashbacks will be retained to cover the debt.
Sometimes, modifications to your order can also prevent your cashback purchase from being properly identified and approved. Because of this, it is recommended that instead of modifying your existing order, you should cancel the order entirely and make a new transaction. Please keep in mind that doing this also depends on the cancellation policy of each store.