I've got you covered, @Js128.

Let's access your QuickBooks Online account using a private mode. Unable to see some options in QBO might cause by a corrupted cache and cookies stored in your browser. To start, the following are the shortcut keys you can use:

• Google Chrome: press Ctrl + Shift + N 
• Mozilla Firefox and Microsoft Edge: press Ctrl + Shift + P
• Safari: press Command + Shift + N

Once signed in, go to the Accounts and Settings window to turn off invoice reminders. Here's how:

1. Click the Gear icon and select Accounts and Settings.
2. Go to Sales menu.
3. Tap the Reminders section and tick the radio button to turn off the option.
4. Hit Save.  

Check it here for more info about the process: Automate invoice reminders in QuickBooks Online.

If this works, let's clear the cache and cookies of your browser. If not, you can use another supported browser. This could be that the browser you're using has a temporary issue with QuickBooks. 

Also, to get a list of all payments and invoices for each of your customers, you may pull up the Invoices and Received Payments Report. Then, customize it so it will only show the info you need. 

Let me know how this goes and leave a reply below. I'm always around to give further assistance to help you turn off the invoice reminder in QBO. Have a good one.