Wow, that is so incredibly hurtful. Such a betrayal.
No wonder you're still processing. I think I do remember you actually but it's a pet hate of mine, that ''have you posted this before?'' accusation, as though mumsnet had a fee paying licence based obligation to provide fresh material 
I know it is precious little consolation right now but the people she smeared you to, they are public servants, social workers. You don't know them luckily. They have closed your case and forgotten you.
I think it is cognitive dissonance to minimise your relationship to ''just somebody I met 12 times'' in order to alleviate any feelings of guilt or shame. So in that regard, minimising your relationship is predictable. It's re-writing history though. Choosing to meet somebody and arranging to meet up 12 times is a relationship. One that ended, but still a relationship.
I think you need to heal the wound of betrayal. Apparently the basis of that healing work is to stand really really firmly in your own interpretation of events while practicing self - compassion.
Journal your thoughts but don't send it anywhere. Then work on self-compassion (there is a really good work book full of exercises by Kirsten Neff phd and Chris Germer phd) so work on that, do the exercises
I have done this journalling exercise over the last three years and I have boiled it down from about 15 pages of what she did what I said how she reacted et cetera et cetera down to ''it is a battle of two narratives'' but I had the support of a good therapist
You're obviously hurting a lot and that is understandable but posting on mumsnet is all venting and no direction. you can heal but you need to invest in to your future by going to a therapist. I really recommend the practice of self-compassion while you stand firmly in your own interpretation of what happened.
You don't need other people to believe your interpretation. YOU KNOW. Remember? But it's the wound that is making you yearn for people to understand what happened.
But people will believe what they hear, what they want to believe, what it suits them to believe.
I do understand the feelings of injustice that come with that. My own mother has done a prince harry on me! smearing me to all the neighbours and relatives. I have decided not to give oxygen to that smear campaign.
So I'm not typing this with no understanding of how much a betrayal hurts.
I had therapy which really helped. I see it now as a battle of two narratives. My mother's is that I'm crazy and mine is that she will not acknowledge that she has been hurtful.
When all is said and done, sometimes communication can merge the two narratives slightly but that isn't going to happen in your case (nor mine 
but keep solid in yourself. You are the strong person in your own corner now.
But stay in your integrity. do not do anything that would give anybody anymore ''material''. Unfollow any of these eejits on facebook, instagram, twitter.
Sto trying to convince people of the truth. It never works! IN the case of my mother smearing me to aunts and uncles (who tell the cousins) I can see that it suits them to believe that because they can then congratulate themselves on their healthier relationships with their adult children. So I will just let them think what they think. None of them are going to be happy to wonder if there is dysfunction in a family. Sometimes you just have to give up and walk away but with strength. You sound like you've spiralled down and you need help getting back up so please treat yourself to therapy.
It's not such a big deal. I've done it twice.