Hey there jm3,
Welcome to the Community. I'd be glad to help point you in the right direction.
I would suggest deleting the credit memo that you created since that amount since it seems to have been automatically applied. This should correct the balance. Additionally, there is a setting within your account that will automatically apply credits. It may be beneficial to turn this off for future use. This can be done by:
1. Click the gear icon in the top right corner.
2. Select Account and Settings.
3. Choose Advanced.
4. Click the small pencil in the Automation section.
5. Uncheck "Automatically apply credits."
I found a link for you that breaks down credits, credit memos, and refunds: https://community.intuit.com/articles/1145640-applying-a-credit-memo-credit-or-refund-for-a-customer.
I hope this is helpful. Please let me know if you have any other questions.