If your flight was cancelled, the airline was responsible (crew shortage, plane scheduling issues, technical faults), and you weren’t informed more than 14 days prior to the flight, you deserve cancelled flight compensation.
This applies to flights that originated in the EU* (even if they landed outside it – except for Switzerland) or inbound flights operated by EU carriers. Flights of up to 1500km are worth €250, from 1500km to 3500km – €400 (the limit for flights taking part completely in the EU), while flights over €3500km go for €600.
Even when the flight is unclaimable, when the wait is longer than 2 hours, the airline should provide free email or free fax, two free phone calls, meals & drinks. Ask the staff at the airport! If it goes on overnight, it should give hotel accommodation as well as the transport to and from. You should not accept vouchers as they might make ineligible for flight compensation!
*EU means the 28 EU Member States and Guadeloupe, French Guiana, Martinique, Reunion, Mayotte, Saint Martin (French Antilles), the Azores, Madeira, the Canary Islands, Iceland, and Norway. It also applies to flights to Ukraine or those on Ukraine-registered airlines.