unlimit the number of submissions

Could you please define your question in more details? By doing this, we can help you better. As far as I understand from your question, you want unlimited the number of submissions; but JotForm's business plan consist of predefined plans which can be seen on the Pricing Page.

Now, you are using the Starter plan which is free, if you need more submission number for one month, you need to upgrade your account by following the steps from the below:

https://www.jotform.com/help/331-How-to-upgrade-my-account

If you need more information about this subject, please don't hesitate to contact us.

Thanks.