Best way to prevent that is to set an account billing alert that will SMS you if your bill goes over $X dollars.
I doubt this feature will ever be implemented, as trying to provide some kind of real-time spend is extremely hard, especially when there are 100+ service bills that need to be aggregated, which usually is a batch process where these things get resolved.
If you are 60 years old, you learned how to monitor your spending in the late 1960s.
Same skill here.