You need to ask forgiveness of Allah, if you promised your mother that you would return but you had no intention of doing sot. If, however, you did ask your mother permission to return to Canada and she agreed to it, then you need not worry about it. Anyhow, the only thing you can do now is to ask forgiveness of Allah and offer some charities if you can as a way of kaffarah.  You may feed ten poor people if you are able to. You should never be remiss in praying for your mother on a consistent basis. May Allah bless us all to cherish the good memory of our parents and pray for them even as they cared for us when we were little—aameen.