I appreciate your effort in following the suggested troubleshooting steps provided by my colleague above, Rlw. I know you're finding ways to get the report you need. I'm here to share another workaround to achieve this sales report specific to your inactive customers in QuickBooks Online.

You can pull up a Sales by Customer Summary, and look for a filter that allows you to select All Customers. Applying this filter will enable the report to encompass every customer in your database, both active and inactive. Please refer to the screenshot below:

Next, export the report to an Excel file to enhance customization options, enabling you to edit the report and eliminate any unnecessary details.

Here's how:

1. Go to Reports.
2. Search for and select the report you want to export.
3. Pick the Export/Print dropdown, then click Export to Excel.
4. Save the file to the download folder or your desktop.

If the inactive customer isn't showing on your end, I recommend calling our support team to investigate this error further and verify if there are ongoing cases. 

You can follow the steps below:

1. Log into your QuickBooks account.
2. Click the Help option in the upper-right corner.
3. Tap the Contact Us button.
4. Choose a topic from the boxes or tap the Ask about something else box.
5. Next, state your concern in the box. Example: Refund concerns. Then, press the Continue button.
6. After that, select between the two options: Have us call you or Schedule an Appointment.

To learn the best time to get in touch with our support team, tap the link for the full details: QuickBooks Online Support.

If you have further questions or need assistance as you navigate the process, comment below. I'm here to help you facilitate your client sales and ensure everything runs smoothly.