I hear your sentiments, james. Please know that this isn’t the kind of service we want you to experience with us.

I understand that you've already tried the steps provided by my colleagues above. Since the issue persists on your end, I'd suggest contacting our QuickBooks Online Support Team. This way, they'll be able to pull up your account in a safe environment and have a screen share with them to investigate this matter further. Here's how:

1. Click the Help menu.
2. From the pop-up panel, go to the Search tab.
3. Click the Contact Us button.
4. In the text box, type in your concern.
5. Click Chat with us.

Moreover, to ensure that we address your concern on time, you can check our available hours when contacting our support.

Alternatively, if you haven't already, you might want to try these steps below to turn off this automatic invoice reminder feature. I'll show you how:

1. From the Gear icon and select Account and Settings.
2. Go to Sales then, tick Reminders.
3. Toggle off the setting.
4. Click Save then, Done to save the changes.
   
   

Here's an article you can refer to for more insights about invoice reminders: Send invoice reminders automatically or manually in QuickBooks Online.

In addition, I'll share with you this article to help you manage invoice payments in the future: Record invoice payments in QuickBooks Online.

Let me know how else I can help you with navigating QuickBooks Online by adding a comment below. I'm more than happy to lend a helping hand. Keep safe.