I can definitely understand your concerns; I know how important it is to make sure you're able to use your phone and avoid any unwanted or unexpected charges while traveling and I'll be more than happy to help look into this for you.
I want to set the proper expectations, these plans are just to minimize the cost of using your phone when you are out of the country, and we cannot guarantee the service once you leave the country since you will not be on Verizon’s network. You are subject to the quality of the network in your destination. There are also settings you may need to enable on your phone to allow it to connect to those international towers. We will gladly look to ensure everything on our end is provisioned correctly though.
Do you have your voice and data roaming enabled (see here https://www.verizonwireless.com/support/knowledge-base-206810/) What happens when you try to use you...