Why am I receiving submissions without payment from some clients?

From at least 2 clients, I have had jot forms filled out, but no money transferred into our Paypal. Why would this be?

It has been on 2 different forms. I included url for one of the forms.

Hello trimistopheles,

When you say that you are receiving submissions do you mean to say that those submissions ended up in "Incomplete Payments" and you manually completed it? 

Please note that when PayPal form is submitted, users are redirected to PayPal checkout page. If the users do not settle the payment, those submissions are marked as incomplete payments. If you manually complete the submissions from the "Incomplete Payments" list, it does not process the payment but just move the submissions record to form's submission page. 

You may like to speak to your customer ask them them to submit the form again and settle the payment when they are redirected to Paypal checkout page.

Thank you!