Why would one submission be complete if we had a typo on the PayPal account?

We had a typo on our PayPal account for the JOTform.   We received one completed submission. The other submissions we received where incomplete due to the payment not going through.  Why did that one order go through?  Did they get charged for the product?  We did not receive payment. 

Incomplete payments refer to submissions where form data was submitted but no payment was made:

https://www.jotform.com/help/135-How-to-View-Incomplete-Payments

If your PayPal account email was entered incorrectly, it would not have been possible to complete payment when submitting the form so all submissions would have been marked incomplete during that time.  Completing the submission manually would not charge the user as payment can only be collected when the form it submitted.  Users who submitted the form when the incorrect PayPal account information was being used would need to submit the form again if they would like to pay through the form.