Check your Form Processing Steps. You can establish Conditional rules that must be valid in order to proceed. For example we added a Human Verification Question to one of our Forms to stop Botz from submitting. The Form Data only recorded those form submits that = the correct answer.
Condition: Processing step will execute when conditions ARE met. Form Field . . . EXACTLY . . . value . .
Only those form submits with the right answer would be processed.
Test emails should be handled through the Tools > Test Content and Deliverability > Test Email . . . When they are handled this way I have yet to see them appear in our Campaign metrics.