I am unable to upgrade my account

Trying to upgrade and continue to give correct security code on back of card and it will not let me upgrade to premium.

Inside of this article you can find out how to upgrade your account: https://www.jotform.com/help/331-How-to-upgrade-my-account 

Make sure that you are using a valid credit card. 

If you are still unable to upgrade your account can you please provide us a screenshot of error you are getting? 

https://www.jotform.com/answers/277033-How-to-add-screenshots-images-to-questions-in-support-forum 

Hope this will help. Let us know if you need further assistance.