Who is the issuer please?
Ok. Were there signs up allowing parking on the pavement?
In that case, the starting point is that he has committed a contravention.
Within the central London Boroughs parking with wheels on the pavement is automatically prohibited unless there are signs up to the contrary.
You can always try to appeal it. Sometimes they don't enforce it.
But if you went to Adjudication that would be the outcome if the facts are as you say.
Can I clarify anything for you?
I am never involved in billing. You would need to email customer services about that.
I didn't think they did free trials but, as I said, I am never involved in that.
All the best.