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.
Unfortunately, it is not possible to block/blacklist a single IP from accessing forms at this time. It is possible to set unique submissions for all users:
However, it is not possible to apply those rules only to a single user.