The there terms and conditions say …..
9 Change of booking and cancellation by the customer
The customer is permitted to change or cancel a reservation only under exceptional circumstances and will incur all resulting costs mentioned under article 9.2. Any cancellation or change of booking by the customer must be made by registered letter or email. Notification by email is only sufficient if it is reconfirmed by STC. Notification is only considered effective when STC is in receipt of all relevant information such as name and address of the person travelling, the booking number and the date of travel, as well as the precise reason and any relevant medical certificates, etc. Relevant information or assurance by the tour guide or any other person not employed by STC will not be recognized.
Cancellation or rebooking of the following services are excluded:
Flights
Events
9.1 Handling fee
STC is entitled to charge the customer a handling fee of a minimum of CHF 60.- per person and a maximum of CHF 120.- per booking for processing a cancellation or change of a booking. Additionally, STC can make booking changes dependent on payment of the fees charged by individual service suppliers such as airlines, hotels etc. STC is entitled to directly debit these additional costs and the processing fee to the customer’s credit card.
9.2 Cancellation charges
Only in exceptional circumstances will STC waive a cancellation fee. This can particularly apply in the case of an online hotel booking where the customer has been notified by the hotel of the latest date the booking may be cancelled without charge. In all other cases of cancellation by the customer STC will, in addition to the hanlding fee (see article 9.1 above), charge a cancellation fee in percentage of the package price, based on the following cancellation deadline before commencement of travel:
Time of cancellation (see footnote 4) Charge to customer
Cancellation > 30 days before date of travel Handling fee to be paid
Cancellation 30 to 15 days before date of travel 20% of package price, but at least the cost of the handling fee to be paid
Cancellation 14 to 8 days before date of travel 50% of package price to be paid
Cancellation 7 to 1 day before date of travel 80% of package price to be paid
Cancellation < 1 day before date of travel or no-show 100% of package price to be paid
100% of travel costs are always payable for rail tickets and airline tickets booked online. The effective date of a cancellation or change to a booking is reckoned to be the date when it can be proved that STC received notification in writing from the customer with all necessary information, according to article 9 above. For Saturdays, Sundays or public holidays, the next working day applies (see footnote 3).