From the EasyJet Website:
If your flight was delayed by more than one hour (but less than five hours), and you did not fly, you can claim for a credit under our delay policy - please telephone Customer Services on 0871 244 2366 (calls cost 10p per minute; calls from mobiles and other networks may cost more).
If your flight was delayed for five hours or more, and you chose not to fly, we will give you a refund of the fare paid via the original method of payment for the journey not made and for the journey already made where the flight no longer serves the purpose of the original travel plan. To claim this refund, please contact Customer Services on 0871 244 2366 (calls cost 10p per minute; calls from mobiles and other networks may cost more).
If your flight was cancelled (please refer to our Carrier's Regulations for full details), and you decided not to transfer onto another flight, you are entitled to receive a full refund via the original method of payment, by telephoning Customer Services on 0871 244 2366 (calls cost 10p per minute; calls from mobiles and other networks may cost more)>.
If you have a complaint or query regarding lost or damaged baggage, or other issues, please telephone our Customer Services department on 0871 244 2366 (calls cost 10p per minute; calls from mobiles and other networks may cost more).