The Berlin oofice for Cubana has closed. The Montreal office is your best bet. They were very helpful when I bought a ticket to HAV from YUL
last year. As mentioned, its located on St. Jacques, and you cant miss it because of the huge neon Cubana sign out front. This is also the office for Sol y Son, Cubana's travel and tour affiliate (also the name of the Cubana inflight magazine) who can book hotels etc. Cubana doesn't have an office in Toronto, but their Sol Y Son affiliate does, located at 160 Bloor St., Toronto, ON
, M4W 1B9 http://www.solysonvacations.com/
Be prepared for some non-competitive pricing though. Cubana relies heavily on inclusive tour companies for its passengers, and not so much on just regular people traveling flight only. I paid CAD525 return to travel on an aging chartered AOM DC-10. If you want to travel to Havana more cheaply, and on more modern equipment, go Air Transat.
Not all who wander are lost....