I have issued a credit note already, want to link our refund to the credit note

Hi Kelly, 

I'm here to help you link your payment with the credit note.

Please make sure that you've selected the A/R account for your payment (expense & cheque). Once done, go to the Receive Payment screen to link the expense transaction and your credit note.

Here's how:

1. Click the Plus (+) icon on the upper-right corner.
2. Under the Customers column, select Receive Payment.
3. Type the name of the customer for the transactions to show below.
4. Place a check mark beside your payment and the credit note.
5. Click Save and close.

Here are some articles for more information:

• Enter And Apply A Credit Memo Or Delayed Credit.
• Record A Customer Refund.

Keep me posted if you need further questions. I'm here to help you.

"Click the Plus (+) icon on the upper-right corner.
Select Refund Receipt."

No, don't use a Refund Receipt; that reduces income which was already done with the c/memo.
The account allocation of the Expense or Cheque should be Accounts Receivable (Debtors). Then create a zero Receive Payment to apply the debit to the credit