This isn't the kind of experience we want you to have with QuickBooks Online (QBO), @entrelac, and @dj in toronto. That's why I'm here to guide you on the next steps you need to take care of this issue.

I appreciate you for performing some of the basic troubleshooting steps to fix the issue about viewing vendor and customer lists. Since it didn't resolve the unusual behavior of the system, let's do another one (disabling pop-up blockers) to further isolate this matter. Here's how to disable pop-ups using Google Chrome:

1. On your computer, open Chrome.
2. At the top right, click More (three dots).
3. Select Settings.
4. Under Privacy and security, click Site settings.
5. Click Pop-ups and redirects.
6. At the top, turn the setting to Blocked.

However, in case the issue continues, I'd recommend contacting our Customer Care team. They can securely pull up your account, guide you with a fix, and initiate a product investigation when necessary.

We've updated our support options in QBO. In case you want to talk to one of our representatives to relay the issue, you need to request a callback. You'll first have to check out our support hours to ensure we can assists you on time. Here's how:

1. Go to the Help menu.
2. Choose Contact Us. 
3. Enter your specific concern in the What can we help you with? field. 
4. Click Let's talk. 
5. Select Get a callback. 
6. Enter your contact details. 
7. Click Confirm my call. 

I've attached a screenshot below for your reference.

In the meantime, I'm adding this article to further guide you in managing your vendor and customer transactions using QBO: QuickBooks Help Articles. It includes topics about account management, banking, and expenses, to name a few. You can click the + More topics button to view other selections.

Let me know how it goes. Drop a comment below if you have other concerns about utilizing the QBO features or inquiries. I'm just around to help. Take care always.