Good day, @wescey.
You can cancel a customer's invoice by deleting it. I'd be happy to show you how:
- In your dashboard, click the Sales tab.
- Select Invoices.
- Select the invoice you want to delete.
- Click the More tab, then hit Delete.
I've also attached some articles you can use on how to send your customer's invoices and record payments:
Drop me a comment below if you have any other questions. Wishing you and your business success.