Hello Avi
Is 3-D Secure enabled on your cards? Please read this discussion:
https://community.sbb-tickets.cc/d/36523-payment-could-not-be-finalized
You can also buy Swiss Travel Passes after your arrival in Switzerland at ticket offices.
Another workaround is to buy them on oebb.at (Austrian Railways) and pay with PayPal. Trainline should also sell passes and accept ApplePay or GooglePay.
Kind regards
Danhiel