Visa help / Coming to Montreal from Colombia (Montréal)

Hi all. I have a Colombian girlfriend and she wants to come to Montreal this summer for an internship. She has been looking into how to accomplish this, but so far she hasn't gotten much encouraging news.

I was wondering if anyone on here had some tips on how they were able to successfully get visas to Canada (for work, travel, or otherwise). She has consulted many agencies that help in the process for a fee but they have all told her that they can't help her. She has been told that it would be much easier to go to Vancouver than to come to Montreal. Is there any reason Montreal is a more difficult destination?

Any help is appreciated! Thanks!