Living in Canada with FaceTime

Canada is so expensive and restrictive with cell phone plans etc.. I know this has been asked a number of times but I am having a debate with somebody who claims previous answers were not correct.

let me specifically rephrase the question.

if both users, a person in the United States, and a person in Canada, are having a FaceTime call either video or just audio and the person in Canada is saying that they are being charged for video or audio calls, is this true?

I am under the impression that as long as both users are using Wi-Fi that the answer is they are not going to be charged and if it is on cellular data then it will just go against their cellular data allotment but I’m not sure if I’m right.

The person claiming that they are getting billed is using Rogers service which is a big cellular service in Canada

please help

if you are in Canada and you are already doing this and you know about Rogers telephone company I would be very grateful to know that specific information as well. I am very grateful