Hallo tharam,
We will look into this matter and refund if applicable.
Please complete the refund form and send it together with the additional purchased right ticket. Is not possible to change the details.
https://www.sbb.ch/en/travelcards-and-tickets/buying-options/formular-erstattungsantrag.html
For tickets obtained at the station or by post please print out your refund request (PDF document) on that website and send it to us by post:
SBB Contact Center
Refunds rail.ch
Spitalweg 19
CH-3902 Brig-Glis
Conditions:
https://www.sbb.ch/en/travelcards-and-tickets/buying-options/online/general-terms-and-conditions.html
Generally speaking, Online/Mobile Tickets may not be modified, exchanged or refunded.
Have a nice day
SamanthaAd