Air Canada responds quickly to legal threats. I suggest paying the $100 or so (for those that don't file several small claims suits) to file a small claim suit online. The process is painless. I have gotten attention from Air Canada that way, and the response is quick and fair.

No lawyer is necessary to file - and if your request is reasonable, then chances are you will win and not have to pay costs to Air Canada for defending their position since resolution should be within a few weeks if your stance on whatever issue you have is fair and Air Canada agrees.