All usage is available in the call history and international calling can be blocked in vPanel. We don't notify users about their usage and leave it up to each user to individually monitor usage.

We recommend that all users monitor their usage.

I will note your suggestion for a total usage notification for consideration for future development. You can obtain usage info in call history now manually or in the call history or usage/unbilled charges area.

I know this is likely not what you want to hear, but it doesn't seem like anything was handled poorly on our end so there's not much we can do. Users are responsible for the calls they place.