Hey @ zozo1
It's difficult for me to know what kind of ticket you have. Basically applies: The tickets are valid for the calendar day that was selected at the time of purchase for each journey made (for example 8.4.18 00:00 – 9.4.18 5.00 a.m.). You can use any connection for the same route on this day.
Exception: The supersaver ticket is only valid for the selected date of travel and the selected public transport connection (train connection).
And if you start at the airport and your ticket start in Geneva, so you need an additional ticket from Geneva airport – Geneva. If you have some futures questions, write an e-mail to ticketshop@sbb.ch or call the Railservice +41 900 300 300. Please tell them your order number.
Kind regards
ManuelaPf