TIL but the California laws are very limited to a subset of items which are already cancellable nationwide. For example, you can always cancel your property insurance and get a prorated refund. OP was talking about hotel reservations which are not cancellable in California. I don't know the situation is in Brazil for cell phone plans but according to the link you posted, it's not cancellable.
They're called things like: "cooling-off law", "buyers remorse law", or "right to cancel"
Some examples: https://cal.lawsoup.org/legal-guides/consumer/contract-cance...