So did this form they sent you a link to not have anything to identify it by?
Like a name or a title...?
Its a called "Review a magistrates' court decision", on the .gov website.
Might have been helpful if you'd mentioned that in your first post.
Did you explain to the court staff that you were unaware of the court proceedings?
I think they've sent you the wrong link and they should have given you this one -
How to challenge a decision by a magistrates
- which is about making a statutory declaration when you've been convicted in proceedings you didn't know about.
Court staff aren't lawyers and don't always give the most appropriate "advice"...