Try the Rouge portal.
Here
Air Canada Rouge
Or you know what pick up that thing called phone and speak to a human !
Air Canada Reservations
Tel.: 0871 220 1111 (Calls cost 10p per minute plus network extras)
Fax: +44 208 750 8495
Mon. - Fri.: 08:00 - 18:00
Sat.: 08:00 - 16:00
Sun.: 07:00 - 15:00
These organic blobs tend/try to be helpful and have access to a variety of fares I do believe.
They can even take a credit/debit card number and e-mailing address