so, a person from SNCF customer service said my ticket was cancelled, somehow, so I got another one just in case
but now, at the station, I've been able to get the machine to send me an email with my ticket (the original) again, so that makes me think it's not actually cancelled? but I'm still kinda worried
I've seen I can cancel the ticket... up to 30 mins after departure? so I guess I can just ask the train inspector after boarding it and cancel then if needed?