Evian les Bains is in France. So it was the French Railways, SNCF, that cancelled, not the SBB. Did you ask the SNCF what alternatives they were offering your?
This is an international trip, so the passenger rights for international trips apply. And these stipulate that in case of a disruption the railway must offer you an alternative. If they do not you are permitted to make your own arrangements, and request compensation for the costs you made. So you might actually be entitled to a refund of your taxi fare.
But that does require that you made an attempt to allow the SNCF arrange an alternative.