Uhm, their website clearly says this though:

You can request for a refund through here and only if you booked your ticket through an AEGEAN point of sale (website, call center, airport). Kindly note that due to the high volume of requests, it can take several weeks to process your refund request and get back to you. Alternatively, you may request a Credit Voucher, whose value will be increased by an additional 10% of the value of your initial ticket.

This links to the below a[plication form. If your flight is canceled you can use this to request the refund.
https://en.aegeanair.com/refund-application/