I know this is somewhat late as you may have filed already but I've located a bona fide site where they can guarantee you a refund by going over your file online. I tried it and they found a loophole for me that I never expected to the tune of $356.78! I also found out that I can delay my filing process for a maximum of 14 days without a penalty even if I already filed. Once you get to the site they fast track your return and intercept it and that places it in a holding pattern until you can redo it... It's a fantastic site that I would recommend to anyone who is reading this. You can find the site at:

http://www.taxtips.ca/filing.htm