I've been marking some tickets as spam within Deskpro, but I keep seeing similar messages. What does the Set Ticket as Spam action actually do?
Marking a ticket as spam just moves it to the Spam filter, where it will be automatically deleted after a period of time set by your admins (1 month by default).
Doing this does not ban the sender, or teach Deskpro to recognise similar tickets in future.
To ban an email address, go to the user profile in the CRM and use More > Delete User & Ban Email.
If you are getting a lot of spam in your ticket email accounts, you should apply spam filtering on your mail server or email service provider, before the email is sent to Deskpro.