What was the original report you've pulled up to show the unpaid invoices? Knowing this would help me explain how this particular report works and how it shows the data.
For now, I have some solutions to help you show your unpaid invoices on your report.
You'll want to check your filters and Reporting period. The data shown on the report depends on these two. These might be the reasons why you're unable to see any unpaid invoices.
Here's how to do it on a report:
On the report, click the Customize button.
Ensure the Report period is set to Last Calendar Year or Last year.
Expand the Filter section.
Set A/R Paid to Unpaid.
Once done, click Save and close.
The data shown also depends on what report you've pulled up. For example, the Open Invoices report shows all unpaid invoices within a specific period. If you've pulled up and customized a different report, you can try this one instead.
Simply go to the Reports section, then type Open Invoices in the search box. You can customize it by following the steps I've written above.
QuickBooks Online uses Targets and Sources to build and show data on the report. For more details about this, you can check this article: Targets vs. Sources overview.