It depends on the method you have selected:
Non-instant refund: it may take up to 15 days - Please note that your order has to arrive at our warehouses and we have to review it manually. Instant refund to bank account: takes less than 10 seconds.
Instant refund to original payment method: depending on the method it may take between 1 and 3 days. The good thing is that it does not depend on the collection.
Instant refund on credit: takes 1 second