When you create the Receipt for the Debit Note, select Accounts payable in the account field on the receipt line and let Manager allocate it automatically
like this
You can’t link both the original payment AND the Debit Note to the supplier invoice as that would overpay the invoice
Alternatively link the payment, the debit note and the receipt to the original invoice and you will get this
That is because a debit note does not create a subsidiary ledger of its own. A debit note is applied to the subsidiary ledger of a supplier to reduce the amount owed to that supplier or record the fact that the supplier owes you money. In strict terms, a debit note posts a debit to the supplier’s subsidiary ledger in Accounts payable.
If the supplier refunds money to you, as in your example, your receipt has the effect of transferring that debit to your cash or bank account by crediting Accounts payable and debiting the cash or bank account.