Entering in a Finance Charge Credit

Our credit card company has issued a credit for finance charges that we were charged last month on this month's statement. How do I enter in this credit properly? I have attempted to have it issued as a credit card refund, but that automatically enters in a credit card charge with it. I have also tried entering in a negative number in the finance charge section, but Quick books will not allow a negative number. The only other thing I can think of is to undo last month's reconciliation, enter the original finance charges as a credit card charge instead, then enter a credit for the finance charge as a credit card refund, and then reconcile from there.