The organiser is to specify how and when refunds are to be processed, and in most cases refunds will already be on their way back to you. Refunds may take up to 5 working days to appear in your account.
For cancelled events, OutSavvy always fully refunds to you the cost of the ticket plus ticket fees
If the event organiser has explained that the event will take place at another place/time and has offered a refund, then it is down to you.