You let them know it's over and that you won't be communicating in any way. Say good-bye and then cut them off.
Yes unless children are involved it is best to completely cutting the person off
I think its better to cut off communication and move on
When something's are over I usually change everything to avoid any communication. What I mean by everything is this: I change my email, phone number etc.
a relationship is only over if both parts agree that its over...