What are my invoices automatically getting mark as paid? I've not changed any settings

Hello there, @elsonsautomotive. Welcome to QuickBooks Community!

Thanks for letting me know that you've not changed anything from QuickBooks Online settings. 

QuickBooks Online offers automation features, including to automatically apply credits to an invoice. This could be the reason why your invoices were automatically marked as paid.

What we can do is double-check if the Automatically apply credits feature is turned on in the Account and Settings. If that's the case, here's how you can turn it off:

1. On the QuickBooks home page, click the Gear icon.
2. Select Account and Settings under Your Company.
3. In the Advanced tab, select the Pencil icon in the Automation section.
4. Remove the check-mark in the box next to Automatically apply credits
5. Click Save. Then, Done to reflect the changes.

Here's the sample screenshot:

However, if the Automatically apply credits feature is turned off already, we can use the Audit Log feature to check if other users in your QBO account mark the invoice as paid. This log shows all transactions and entries entered, edited, or deleted within the program. Here's how:

1. Go to the Gear icon.
2. Select Audit Log under Tools.
3. Click the Filter drop-down arrow. 
4. Select All Users and correct dates.
5. Tick the Transactions box. Then, choose All Transactions.
6. Select Apply.
7. Then, find the invoice that was marked as paid. Then, click View to review all the information.

You may want to check these articles to learn about the different way handling transactions depending on the scenario:

• Create and apply credit notes or delayed credits in QuickBooks Online.
• Set up and send progress invoices in QuickBooks Online.

Please let me know how it goes. You can go back here and post additional questions about invoices or any transactions. I'll be around to help you sort it out. Take care and stay safe.