Form Spam

I keep getting form spam even though I have logic created that does not display a submit button on the form if certain key phrases are present in the comments field. How is this form being submitted through the back end? Is there no logic preventing submission if no legit form button action was pressed? I have a license that is currently expired, so Formcraft won’t allow me to submit a support ticket, but am not interested spending more money unless there is a solution to the issue.