monitoring data usage on Verizon MiFi hotspot

I support a company that has several field users and they all share a data plan (30GB) on their corporate Verizon account.
Every so often a user or two will use up a large portion of the data, resulting in overages and additional cost, which drives the owners crazy.
Is something I can use to monitor bandwidth usage and websites associated with high bandwidth usage. It would really be nice if Verizon could provide something other than GB used, such as websites visited. I'm sure this would be too much for them to provide, but it would certainly help in this case, especially since they could be using this hotspot for their home computers also.

I've seen things that will monitor usage per application, but that doesn't help because the main thing the user uses, validly is Chrome to connect to a client's "utilisphere" site. I"ve heard Utilisphere was a data hog but this month the user used 26GB of the 30. Another user that uses Utilisphere only used 8GB

So now they have me looking at browsing history, which has all been deleted, except for several items, one of which was a search for "how to permanently delete browsing history". Kind of funny that would be left there.

So I used shadowexplorer to get the chrome history and viewed it with chromehistory viewer and saw that there were a lot of things that obviously weren't business related. Facebook, youtube, news videos, etc.

Something that comes to mind as far as reporting visited sites is "content protect", the business version of net nanny, but the reporting is slow and klunky and also gives no bandwidth usage info.

Any thoughts or suggestions are greatly appreciated.