None of these rules mean that you have to accept poor treatment of you by an individual.
Not returning calls, or letters etc is basic rudeness not adverse systems !
You haven’t accepted the poor treatment of your ex although its tough – you got out – you did it – you were strong enough.
Don’t accept it from idiots behind desks who can’t be bothered to do their jobs properly. Yes I know that was judgemental of some people in ‘the helping’ professions, it was meant to be