I too get the occasional annoying email communication. I'm not sure how they are generated, because a few are the same/almost the same in content and invariably from the same source/person. I have always assumed that the individuals have nothing better to do than complete an online enquiry form in the hope of generating a response (which never happens - the form provides some for of annominity for the receipient, unless a response is made).
I suppose one solution would be to set up a "Dummy" email account for the purposes of receiving enquiries through the online form and reviewing incoming emails once a week/month - weeding out the genuine from the others.
All the best
Not sure if this would help but for many years i have used some third party software called Mailwasher - it was developed in NZ around 20 years ago. It links up with your mail server(s) without you being in the mail account and learns as you use it what is spam and automatically flags it up for deletion next time, then it just clicking on the 'sponge' to tell it to delete or 'wash' all the 'dirty mail'. You can flag up either individuals or domains for the black lists or as friends. Mailwasher gives me an overview of all my accounts and i can delete anything that i don't want to get through to outlook.