Thanks for joining the thread, @Mark381.

I appreciate you for following the steps provided by my colleague above. There's a possibility that the Automation feature is turned on, that's why you're able to see a reduction to the receivables reports in QuickBooks Online. 

It would be my pleasure to help walk you through the steps on how to check the settings. Here's how:

1. Go to the Gear icon on the upper right pane. 
2. Select the Account and Settings tab.
3. Choose Advance, then locate Automation. 
4. Verify if the Automatically apply for credits is On. 

Once verified, nothing to worry about your reports because you're on the right track. If you don't want to automatically apply the credits to your existing transaction, simply turn off the feature. 

However, if the Automation is already turned off and still unable to apply to credit, I suggest performing a few basic troubleshooting steps to resolve the issue. To start, access your QBO account using a private browser. At times, the stored data can cause some problems in your browser's web pages.

Use these shortcut keys: 

• Ctrl+ Shift + N (Google Chrome)
• Ctrl + Shift + P (Mozilla Firefox)
• Ctrl + Shift + P (Internet Explorer)
• Command + Shift + N (Safari)

Once logged in, go to the Received Payments and check if you're able to apply the credit memo. If the private browser works, you can clear the cache depending on which browser you're using through this helpful article: Delete Temporary Internet Files. Using another compatible browser is a good option too.

Let me know if there's anything else you need about QuickBooks by clicking the Reply button below. I'm always here to help.