This is my mantra as well. All their authority is peer-conveyed. Once you do not recognize it, it does not exist for you.
https://www.youtube.com/watch?v=eEIJ3YqPbqg
Have you considered blocking their texts and emails? It is quite a satisfying way to take your power back. They don't even get to harass your voicemail. It irritates the heck out of them.