We had an issue with Verizon on this trip. I had added the Canada plan to our existing 450 minutes of voice right before we crossed into Canada. We don't use our Verizon phone very often, thus the small amount of minutes. So, right before our next billing cycle in early July, we got online to increase our minutes as we were using them up pretty quickly talking to the kids and other stuff. When we did that online, it invalidated our Canada coverage and they billed all of our calls made in Canada with roaming and long distance to a total of $389.00 +/-
Since the Verizon phone is in my name, I got to deal with them. It took about 10 or so days but they reversed the excess calls and cleared all Canadian charges except the $20.00/month fee.
So, advice to those coming into Canada, call Verizon if you want to change anything rather than using the online method.