Once a refund has been authorised by Little Nation it will automatically go to Afterpay for processing.
Whenever the refund amount is equal or smaller than your AfterPay balance, refunds will be applied to your outstanding AfterPay balance.  The refund amount will be applied from your last installment backwards until it is fully discounted.  This means your final payment might be reduced to zero, but the rest of your payments stay the same. 
If you have paid all your installments, you will receive a refund back to the card linked to your AfterPay account. You will get a notification from AfterPay to confirm the refund was processed.  Be aware that refunds to your financial institution can take up to 7 business days. If you have additional questions, please contact AfterPay.