I used Air Canada, direct flight, honestly I didn't even call before, I know for a fact that Aircanada accepts RTDs, once you are in the airport just go to check in using the counter because the self check-in machines don't read the RTD, don't agents on the phone, are in a call center and probably hav no idea what they are talking about, i would recommend asking them to direct you to a supervisor because of the conflicting and contradicting info you are getting.
I agree with you! The agents on the phone had no idea. They kept referring me to my embassy here in Canada. I said my embassy is irrelevant. I will do that, thank you for your feedback.