> how could I use more than 6 GB of data????
Data usage is not a reflection of what you as a user actively or consciously consumed. It is a reflection of how much data actually navigated across the VZW network to your Jetpack, with or without your knowledge. In most cases high data usage is the result of an application on one of your PCs that is simply running wild or attempting to download, failing and retrying until you stop it or it succeeds.
> And of course, many of these messages have come in the night, when I'm not even on the computer/wifi!
Data usage reporting is delayed, it can sometimes take a few minutes to a few hours for reporting to kick in and warn people about what happened. As long as your Jetpack is online it is vulnerable to start chatting with your PCs and consuming internet. The only way to stop data usage is to power off the Jetpack completely when it is not in use.
> Sometimes my computer security says that the jetpack is NOT SECURE?
I have no idea what that means.
> Maybe that is when someone/something besides me is using data from it?
Your PC would have no way of knowing it someone else was using the Jetpack or not. Separate devices with no direct connections into eachother. The jetpack is a gateway to the internet, nothing more to your PC.
> And I have tried turning the jetpack off when I get one of those overage messages....
It is a good habit in an overage situation to learn to turn off the Jetpack immediately after you are done using it. This will minimize the chance of your PCs chatting away in the background however they please.
> ..NOW am waiting to hear solution from Verizon on unexplained data usage on many of their jetpacks!!!!!
You will not hear a solution from VZW on this subject. VZW will only provide you with summarized data usage reports. The information that you need to solve this problem must be obtained on your own with personal data usage monitors. This situation, like all data usage situations, is like a garden hose that has been left on. Its not VZWs obligation to tell you which of your hoses are on or who was the last one to drink. All VZW will tell you is how much water has been pumped to your house and bill you accordingly. At this time you have to discover the actual source of the problem on your own.