Mine was a bit tricky - the email triggering source finder was one part - how to stop it was another altogether. I am still working with NetSuite on this but they mentioned something that does not make any sense. In short - our emails were getting triggered from a workflow which was inactive - NetSuite said that the workflow should be suspended on top of being Inactive - the reason they gave is customers which still has the workflow as an active workflow may trigger it if the trigger for the workflow is met - but my reply to them is that it does not make any sense that the workflow will go back to the state where email was sent (workflow is active showing in 2nd state, but email is triggered in 1st state)