Ellie, maybe she just doesn't do that; it's possible her family only acknowleges when an answer is required. Maybe you should just say something along the lines of, "I just thought I'd ask, and maybe I'm being a bit overreactive, but when I tell you something, could you acknowledge it in some small way, just to let me know you heard me?" It's possible she really doesn't think it's a problem.

The "Mom" thing...I called my mother in law "Helen". I didn't even call my own Mother "Mom"!