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 only way to revert a form to a previous version if by using the Revision History tool: https://www.jotform.com/help/294-How-to-View-Form-Revision-History
Does someone besides you have access to your account?
You can view your account history by click on the Person shape icon, then on Account, and going to History tab:
You can browse by Logins, Form Modifications etc:
I would recommend you to also update your account password by going to the Settings tab.
If think this is something that happens automatically, try:
1) Clearing forms cache: https://www.jotform.com/help/229-How-to-Clear-your-Form-Cache
2) Cloning the form: https://www.jotform.com/help/27-How-to-clone-an-existing-form-from-your-account
Let us know if you have more questions.