Help with €50x2 metro fine?

In short -

• Landed in CDG airport by plane

• Had a booking for the fast rail from CDG to disneyland

• Entered the wrong train platform (went into the metro platform instead of the fast train platform)

• Big crowd on the way in so we just followed them - the gate stayed open for us due to the crowd (maybe we entered under someone elses ticket in front of us?)

• within 45 seconds realised our mistake - headed for the exit gate of this platform

• argument ensued with rail security for no metro ticket to exit the platform - explained situatuon to them and shoed them ticket for the fast train- they were not having any of it

• €50 fine (x 2 people - so €100) issued - paid on the spot

• Missed the fast train and had to re-book for an hour later (another €25x2)

I have subitted an appeal to SNCF today. Do you think I will be successful?