. What To Do If Harassed On Instructables
You can't block them from commenting on your work, just from sending you PMs.If another user is causing trouble, contact the staff, or one of the "usual suspects" for help.
There is not much you can do to control what other persons look at.If you're being harassed or bullied send an email to the administration and if it's serious the can ban them. Maybe just a warning from them would be enough.https://www.instructables.com/about/contact.jsp
Are you being stalked/bullied?