I’ve had the same experience and parked myself in front of any counter with an agent until they help me, or find someone directly (ie phone call) who actually is willing to help. Last time I was stuck in YYZ around midnight at least 4 staff told me to go elsewhere. Lots of staff but no one wanting to help. Start tweeting or facebooking pictures and stories of passengers in trouble might be your best bet if you have no luck on the ground. Tag anyone and everyone you like, might get called an attention seeker but really you desperately need attention from AC!