1. Work out how the refund actually arrived. A check or bank transfer back from the vendor needs a different path than a credit applied straight back to the card you paid with. Getting this wrong is the single most common mistake here.
2. For a refund that hits your bank: create the Vendor Credit first. Go to + New > Vendor Credit, select the vendor, and enter the same category or item the original expense was recorded under, for the refunded amount.
3. Deposit the refund. Go to + New > Bank Deposit, and on the deposit line, choose Accounts Payable as the account, with the vendor listed as who it's from, for the same amount.
4. Link the deposit to the vendor credit. Go to Pay Bills, select the vendor. QuickBooks shows both the open deposit and the open vendor credit as items you can apply against each other. Select both so they net to zero instead of sitting as two unrelated open balances.
5. For a refund that lands back on a credit card instead, use Credit Card Credit directly. Go to + New > Credit Card Credit, choose the vendor and the original expense category, and enter the amount. This reduces the card balance and the expense in one step, with no deposit or Pay Bills linking needed.
6. Confirm the vendor's balance afterward. Open Expenses > Vendors, click the vendor's name, and check that the refund shows up correctly and nothing's left sitting open that shouldn't be.