But she didn’t hassle you
Bungle73 . Unless I’ve misread your posts, you approached her becasue your ticket didn’t work in the machine, she said the machine was correct, you explained why she and the machine were wrong, then she let you continue your journey.
It does look as if she made an honest mistake; she accepted your explanation and let you through.
You then wrote a letter of complaint about her not knowing the finer detail of the ticketing criteria, you received a letter agreeing with you that a mistake has made and that it would be addressed with the employee.
That doesn’t add up to her hassling you. She made a mistake, and backed down.