Making long distance phone call on FaceTime

FaceTime uses the internet, so no charges to connect with anyone anywhere.

I just got a $22 charge for an international call on FaceTime on my T-Mobile account. I notice previous calls to this number had a little camera next to them, but this one had a little phone. I answered the call on FaceTime on my desktop.

You may have answered using FaceTime on your computer, but it was using your cellular connection from your phone. That's different than making a FaceTime video call.