Renting out a place in November and December can be tough so that might explain your problems.
But, I also have a couple of other thoughts.
Are you also advertising and posting ads in French for a rental in Montreal, where the majority of the people speak French at home?
If you're not also adverting to the French speakers, then you've already lost the chance to rent it to the majority of the renters before the battle even started. Can't you put the same information in French and then in English in the same ad?
And, it seems like your Kiiji ad is already expired.
I wouldn't start off your ad by telling them to contact you via phone, email, or text. You should leave that information till the end after you've built up the desire in the reader to rent your place.
When you write the ad, you should start off with the best thing about your place- the reason why somebody should rent your place over another place. It sounds like the best thing is the location so why not start off the ad with that? When I read the ad, I wouldn't have known it was located in the heart of downtown Montreal.
If those are real wood floors in the picture, then I would write that you have wood floors in the ad. If I see those pictures but the owner doesn't mention there are wood floors, then I just assume that the floors are laminate or vinyl.
I wouldn't change it now, but the white appliances seem in-congruent with the downtown loft with exposed pipes vibe of your rental.
Finally, are you sure about your comps?
When you said comparable rents go for $2500-$3000, are you looking at 2 bedrooms or 1 bedroom comps? You're advertising your place as a 2 bedroom, but the open loft feel really makes your place seem more like a 1 bedroom and not a 2 bedroom.