RE: This is an old question
I missed the flight to Montreal also, but the Air canada refused to pay the hotel fee, they said it is the fault of Immigrant Office in stead of theirs. It is free to book the next day's flight, but we have to pay the hotel ourselves, you can share the hotel room with other people who also miss the flight, the price is 110CND/night for 2 rooms
two years ago in Vancouver, we have 3 couples to share.
Good Luck!