Cancellations and refunds are fully automated.
Unfortunately sometime providers have to cancel bookings (eg. bad weather), when it happens you get a notification straight away and the refund is automatically processed as soon as the provider cancel the booking within Leezair Marketplace or within his reservation system.
note: If the supplier forgot to cancel the booking or just gave you a call, you can always remind him they can directly do it on their hand.
The refund will be processed into the same card account you've paid with on the same day (it can take up to 2-3 days with certain banks, especially overseas).