As I already said, you can't formally decline your ballot at the Federal level. Also, as I already said, I might just run, myself, so that I have someone to vote for. That wasn't a joke, though my campaign most certainly would be. If I don't, then my current choice is Trudeau.
You have a choice between the guy who is currently running the country by lying to you and pissing on actual politically conservative ideals, or giving the guy who hasn't actually damaged our nation yet, but who you seem to have a personal dislike for, a chance to not do the sort of thing that the current guy is doing. Your choice is to vote for the guy who has actually hurt us, because you think that the other guy might? I find that unfathomable. Even laughable.
The 'thing' that I have against Harper is that he's a hypocrite, a liar, and has dangerous political ideas that the United States has already proved are unworkable but, based solely on disproved partisan beliefs, he thinks will somehow work for us. Contempt of Parliament. Statutory minimum sentences that, when previously enacted, had already resulted in things like multiples of 'time served' for pre-sentencing imprisonment. Carefully 'managing' his Cabinet, so that they don't actually tell anyone anything. Law changes that would see us start to follow the United States in the percentage of our population that is behind bars, when they are actually moving away from those laws because of the idiocy and costs involved.
It's time that people start to look at the cold facts behind their beliefs. I think most would be surprised at just how much of what they've taken to be fact, doesn't actually stand up to real scrutiny.