Hello Caleb
These are two different types of tickets, this is why there is a price difference.
And, apparently, Mt. Rigi has a special round trip offer that is less than the total of two single tickets. The SBB webshop does also offer the round trip for a total of CHF 78.
Please contact SBB using the following form:
https://sbb-tickets.cc/en/help-and-contact/customer-service/praise-comments/reklamation.html?stepId=3.17
Only SBB is able to decide whether a partial refund is granted under these circumstances. There is no guarantee, whatsoever.
Finally, you can purchase the tickets in advance, there is no need to do so in the very last minute. And, EasyRide is not recommended for mountain trips, you have learned it now.
Kind regards,
Roland