What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
The incomplete payment submission usually means that user decided to not to complete the transaction on the PayPal payment page. Please take a look at the following guide.
However, if you actually receive payments for these 'incomplete payments' then the issue is most likely related to the IPN configuration of your PayPal account.
If you need any further assistance on this, please let us know.