viola....I get it that you don't want to "control" her relationship with her father....and, I agree with you, in principle....
I do have another thought that I would like to pass in front of you....since his use of his time communicating with her to excess, and is being sooo manipulative to the point of deliberately putting a guilt trip on her and trying to make you a bad guy and putting her in the middle....
Could this not disturb her and trigger some caretaking rile for her....I mean, you know hoe difficult he has made life for you---would it not be the same for her, now? You were able to get advice from us in your pain....
My point of this, is this: While you don't want to control her, in this matter....you are still the mother...and she is just 17yrs.....and still needs your advice and wisdom...as a consultant in her life....
How about suggesting to her that she make some sort of schedule with her father, to place some boundaries. Like, maybe, just a few, short, conversations in a week....and testing only once, at, say six o'clock ...so she can get her schoolwork, etc, done....
I would say that she is a perfect candidate for Alateen.....if there are any in your community....she would surely benefit from it....