JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
I'm sorry for the trouble caused to you.
Do you get any error message when you input your credit card details? Can you please share a screenshot of the payment screen what you see? The following guide should help you how to upload image in forum post: http://www.jotform.com/answers/277033
I would suggest you to please sign out form your account and then sign in again before attempting to upgrade your account again.
We will wait for your response.