Thanks for reaching out to us here. I'll be glad to share more info so you're on the right track.
The option to record interest income on a refund isn't available in QuickBooks. As a workaround, I recommend entering a journal entry to record the interest. For reference on how to enter the journal entry, I encourage you to check out this thread here.
You're welcome to ask other questions in the comments below. I'll be on standby.