Technically, they can even detain you the moment you enter embassy building. Yes embassy property is considered part of your land, so if you enter there on your free will Canada cannot help you (without sparking a diplomacy incident).
And by the way same right goes for diplomatic cars and planes. (in case you are wondering how could they escort you outside of Canada).
So the only thing you can do is to check with whoever wants to get your property if some kind of letter giving right to somebody else to deal with this matter in your absence will be accepted. Obviously if it is signed in front of a notary public in a foreign country (in Canada in this case)