Welcome to the Community, HeitherMarie1.

If you’ve already turned off the email reminders in your QuickBooks Online account but still send them to your customers. Let’s perform troubleshooting steps to resolve your concern.

Start by logging in to your QuickBooks Online account using a private or incognito browser. 

You can use these keyboard shortcuts below:

• Google Chrome: Ctrl + Shift + N
• Safari 11 or newer: ⌘ + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + N

From there, check on your customer’s end if they still received some email invoice reminders. If they don’t, return to your regular browser and clear its cache. Clearing your cache helps clean up browser cookies that block web pages from loading. 

In addition, you can check out this article with information on recording the invoice payments received from your customers: Record invoice payments in QuickBooks Online. 

Feel free to leave a comment if you have other QBO invoice-related related. I'm always available to assist you.