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.
Since your current credit card was already charged we will need to cancel the subscription in order to provide a refund, this way once the account has been set back to free you could upgrade to the same plan with the updated info.
Do note that you could simply change the current credit card used by going to the billing section on your account: https://www.jotform.com/myaccount/billing
And clicking on the "Change Credit Card" button, so the next payment is charged to the updated card.