Ok, so Expedia answered and gave me a voucher valid for 1 year to use that money on any other ticket (more expensive than this one), i can change the route and the destination and even the dates, till 1 year since the day i bought it. That's good news.
Bad news: only flights with Aegean (which again, i had just one experience, BCN-ATH A321 SX-DVO in 2010) which was very good. And only from DME. So i'll try to find something rather exotic, using the old birds from OA.