Hello LondonTrain,
If you buy a ticket as a visitor without an SBB account, so I mean a Swiss Pass login, then your ticket is not visible on the SBB APP because it was purchased as a guest.
But when you buy a ticket as a guest you have to give your email and you will get the ticket by email and also a purchase receipt by email.
If this is not the case please contact us by phone:
Tel. 0848 44 66 88
(CHF 0.08/min.)
(available 24/7, sometimes you may be required to wait)
Or when you call aud from abroad: +41 51 225 78 00.
I wish you a nice day,
Kind Regards MelanieD