To record interest charge reversals for your credit cards in QuickBooks Online (QBO), you can make a refund for your vendor.
Here's how:
On your QBO account, click the + New button.
Choose the Credit card credit.
Select the appropriate vendor in the Payee field,
From the Bank/Credit account ▼ dropdown, select the credit card to which you received the refund.
Enter the Payment date, refund Amount, Tax and Category.
Choose Save and close when done.
To learn more about how to record a refund or credit from a vendor, I recommend checking this article: Enter vendor credits and refunds in QuickBooks Online. It contains different scenarios for entering returns depending on how you record your purchases.
For your future help, I'd also provide an article that helps you reconcile your account in QuickBooks Online.
Come back if you have any other questions about recording the interest charge reversal for a credit card. I'm only a reply away.