+353 1 562 1043 is the only number to call. If they don't help, hang up and try again.
This is a travel agent ticket so you must deal with the agent, Aer Lingus customer service can't do anything for you full stop, only the Rewards line can
Clearly state you want to cancel, give the full booking confirmation code, not the Aer Lingus one starting with 2, these calls are recorded, they seriously are..