Why do you not want to answer this thread?(Your answer will be sent to Jeanette and Aytekin)
You can add a Captcha field on your form to prevent spam bots only submissions on the form.
User guide: How-to-Add-a-Captcha-Field
Another option is to set the form to send unique submission only.
User guide: How-to-Set-Unique-Submissions-on-a-Form