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.
If you would like to change or update your email address used in your JotForm account, you can do that by first logging in, navigate to Account->Profile->Email
You can change or update your email there.
For the payment method, I see that you are currently on "Free" plan, you can proceed on upgrading your plan by following this guide: http://www.jotform.com/help/331-How-to-upgrade-my-account. From there, you'll have an option to choose a payment method, just select credit card and add the details of the new credit card there.
Do let us know if you need more information on this.