I [know how to communicate with students] and Cumberland and the UVSS do too: class talks. Just take five minutes, especially at the beginning of large 100–200 level classes. You have so many directors in the UVSS; surely you can do this even without the help of volunteers at your disposal. Have a permanent tabling set up at the entrance of SUB; handbills; informative town hall sessions with incentives; aggressive postering and promotion — use the Facebook promotions targeting UVic students. Any social media pro will tell you they absolutely work. And this is just the basics in union communications.
Even if you don’t do all of these or only some of these, you could reach a larger portion of students. Only sending out vague, purposefully misleading emails and using “social media accounts” is revealing and reeks of apathy. If student well-being is not your primary concern as a union executive, you should not be in this position of trust: plain and simple.
If you suck at communications, amend or replace your current communication strategy (if you have one) or hire someone better. If you feel like you came into this not knowing enough about the job or how to manage this kind of task, question and fix the handover process and the UVSS staff that should have better equipped you for this role. But don’t for a second act like this is out of your hands or there is nothing else you could have done.