I have my iPhone 6 linked up with my MacBook Pro so when someone calls me, the FaceTime app opens and it gives me a notification on my MacBook screen to accept the call - rather than holding my phone to my ear for several minutes. I use my headphones and the built in mic to speak. Now I'm expecting a call from the US (I'm in Canada) and I should be at my computer (*on Wi-Fi*) when they call. I want to be careful otherwise I could have a huge bill. Could I somehow be charged extra on my bill for this?