Call them out on Twitter.
"You took me to court while I had a perfectly valid ticket, withdrew the prosecution when your incompetence was exposed, and now refuse to cover my losses. Is that how you treat a hardworking, honest fare-paying passenger?"
Unless you have loads of followers, it will make no difference whatsoever.
Only going to work if you've enough Twitter followers to make them pay attention. In all seriousness, if it were me I'd try to get the story in the national press (something like BBC You & Yours, or Watchdog, or perhaps The Guardian). There's no outstanding legal case, so no reason for them not to take it up, and it would hopefully make the TOC pay attention as well as attracting some sort of 'goodwill' payment to the affected passenger.
The BBC were interested in this case, but XC have been persuaded to keep it out of court it's no longer particularly newsworthy, and - as is often the case - I've not heard anything from the passenger to say they are interested in taking up the option now anyway.
The media are not interested in a complex case where the case against the customer was dropped. Well, they might be if there was an audio or video recording of the incident. But as it is, it's just not particularly interesting to them. I think if the customer was interested in doing an interview and if other forum members were prepared to be interviewed, with a lot of effort I could perhaps get a few media people interested.
But I am becoming increasingly fed up of chasing these things and getting no good results.
There isn't anyone or any organisation with the power and determination to stop train companies threatening valid ticket holders with prosecution. I can get people out of these situations but it is frustrating that, even with various contacts, I am unable to actually do anything to get these incidents to stop.
I sometimes wonder why I bother to get worked up about it, it doesn't seem to achieve much. They will never change...