Let's make sure you'll be able to match the purchase order to your bill, Toonces.

Under normal circumstances, QuickBooks matches uploaded bills to existing bill transactions or any existing purchase order. The program will determine if an existing vendor bill matches the vendor name, amount, and date, and display the information for confirmation. It's possible that the purchase order is linked to another bill, that's why it's not showing on your end. Since you've already performed the Verify and Rebuild tool, I suggest reaching out to our phone support team so they can investigate further. They have the tools to pull up your account in a secure environment. 

At the same time, you may also need to review your accounts in QuickBooks to make sure they match your real-life bank and credit card statements. For more information, please read this article for more information: Reconcile An Account In QuickBooks Desktop.

Feel free to let me know if you have any concerns when matching transactions. I'll always be right here to help.