Why inactive customers become deleted?

RenjolynC - thank you for your detailed response. It works just fine! I didn't notice the GEAR icon above Action because I was overcome with anxiety at the time. Hats off to you!

I have followed this process; however, it is not showing all invoices for the inactive customer.  One invoice is listed in the sales/invoice panel, but not the remaining 6 invoices.  All of the invoices show in the invoice report. How can I get those to appear?  Do I need to make them active again?

I appreciate you for following the steps shared by my colleague, @Ahyre.

Yes, you'll need to make the customer active again to see all the transactions that you've created. Let me show you how.

1. Go to Sales, then select Customers.
2. Above the Action column, click the small gear icon ⚙, then check the Include inactive box.
3. Find the customer and in the Action column, select Make Active.

Once done, you can make the customer inactive again.

However, if the transactions doesn't show, I'd suggest logging into your QuickBooks account through a private browser. This will help us determine if the problem is related to the browser's settings. 

To open a private browser:

• Google Chrome: Press CTRL + Shift + N.
• Safari: Press Command + Shift + N.
• Mozilla Firefox: Press CTRL + Shift + P.

 If it works, go back to your main browser and clear its cache. Alternatively, you can use other compatible browsers. It could be that the one you're currently working on has a temporary issue with QuickBooks. 

Also, you can run the Invoices and Received Payments reports. This will provide you the details of the payments you've received and the invoices that go with them. Just go to Reports and select Invoices and Received Payments. 

For complete guidelines in sorting and customizing your reports, check out this article: How to Customize Reports: Basics, Sorting & Date Ranges.

Please let me know if you have other concerns. I'm just around to help. Take care always.