I have a customer disputing the receipt of an invoice after having received a late payment notice. Is there any record of the invoice being sent in quickbooks?

Good morning, @charteroaktel. 

Thanks for taking the time to reach out to the QuickBooks Community for support. 

You can use our Transaction list by customer report to see all of your sent invoices. I've included some steps to use this report below. 

1. Click Reports from the left pane.
2. Enter the report name in the search box and select Transaction List by customer report.
3. Press the Customize.
4. In the Report period, set the date.
5. From the Rows/Columns section, put a check mark on the Sent box.
6. In the Filter section, tick the Transaction Type box and select Invoice.
7. Put also a check mark next to Sent, and in the drop-down hit Sent.
8. Once done, click Run report.

That should do it. Please don't hesitate to let me know if you have any questions or concerns. I'm always around to lend a hand. Take care! 

I'd rather check the Last delivery stamp on the invoice page than open that report. It shows the date, time, and email of the recipient. I think it will also tell you if the invoice was not successfully sent.