I have 3 QBO accounts, all Plus. In two Bill Pay by Melio works great. In the third it is not an available app to install. Bill.com seems to be stuck in my system...

You may create a separate MP account to connect with your 3rd QBO account for free.

https:// melio.grsm.io/quickbooks

I actually have 3 already, one for each company.  However, two of my QBO accounts let me add the Pay Bill by Melio app and pay bills online inside of QBO seamlessly.  However, the third does not show the Pay Bill by Melio app available, so I can't download it and I'm told it's be my account thinks Bill Pay by Bill.com is installed but it's not and the Bill.com guys can't figure it out either.  Basically, all 3 companies are pointing at each other...

Hello, Bcdickerson.

I'd like to share some steps where you can sync the application.

Here's how:

1. Go to this link: QuickBooks App Store.
2. Find the app in the search field.
3. Click the App to see the details and click the Get app now button.
4. In the Let's get you set up to use page, select the company you want to integrate the app with from the Search for a company or firm drop-down menu. 
5. Click Next and then select Connect.

If you're still unable to find the application, I recommend reaching out to our Customer Care Team. They can check the account further. 

Before doing so, please check our support hours here. Then, follow these steps:

1. Click the Help icon located in the upper right-hand corner.
2. In the Help window, click the Contact Us button located at the bottom.
3. Enter your question and click Let's talk.
4. Choose either Start a chat or Call us.

If you have the new QuickBooks Assistant help update, you can follow these steps:

1. Go to the Help menu, and select Talk to a human.
2. Choose Talk to a human again. 
3. Proceed with I still need a human.
4. Click the Contact us link.
5. Select either Start messaging or Get a call.

Please let me know if you have any follow-up questions or other concerns. I'm just a post away to help you some more.