Hello involuntary, Welcome to the Community.
The corporate level forum Mods typically work 8am to 5pm eastern, M-F so it will be Monday at the soonest before getting an official response.
"I just know these companies track what sites have been visited":
Without a court order tracking the detailed usage of a subscriber could have some grave privacy concerns.
Hughes as an ISP is contracted to supply and support data to the point of the Modems LAN port. If a subscriber chooses to share that data with other devices by adding a Router and thereby creating a "Network", it is incumbent upon the subscriber to administer and maintain that Network.
As you stated, you have Glasswire installed on the computer(s) and that is good in the respect that it help rule out that machine.
If you have a simple "network" like that shown below .. a single computer directly connected to the modem .. there exists only a single "connection path" for data to be used:
(click on picture for larger image)
Monitoring software such as Glasswire can be installed on the computer so that all traffic along point A of the connection path is measured and can then be compared to the usage meters in the Hughes Modem, point B. The two should track very closely. In fact in many cases the Hughes Modem will record less usage than that of point A due to some activity benefiting from "compression".
Choosing to install a Router at the heart of YOUR NETWORK really complicates matters as it multiplies the number of potential connection paths on several fronts and introduces vulnerabilities of its own.
Our Network now looks like this:
We still have the same "Data Toll Road", point B .. the Modem through which all data must pass and be charged against our allowance but we now have added the potential for multiple wired devices (point A) and the toughest of all MULTIPLE WIRELESS CONNECTIONS and some hardware aspects that are sometimes overlooked.
Lets take a closer look at a Router:
There are three potential areas of use:
#1: The Routers hardware, settings and "internal services".
Several well known brands of Routers have had vulnerabilities posted in the media recently. There would include Cisco, D-Link and Netgear.
Check your Router's manufactures web-site and do a manual check for firmware updates
Disable any auto-update functions as these have been known to get stuck in a update/fail/update loop using large amounts of data. Because this is happening at the router hardware level the user would most likely be unaware of this activity.
Other settings that should be carefully scrutinized are:
> Make sure that the Routers GUI access has had the default username and password changed <
> Disable all Guest Accounts <
> Disable WPS <
> Disable Remote Access <
> Disable all internal "sync" and "cloud" functions <
The above services can provide a "backdoor" to your internet connection
> Carefully scrutinize the settings and weigh the value of any "internal protective services <
Some of these can use large amounts of data again without your knowledge
All of the above will connect through the Routers WAN port and directly to Point B, the Modem. You won't see this activity but it will be charged against your monthly allowance.
#2: Wired connections
Anything and everything connected to any of the Routers wired LAN ports will have wide open access to your data allowance. Each computer will have 65,536 com ports that can connect. Some will be the result of PROGRAMS that you know are open and can see in operation. Many more will be in the form of PROCESSES, running unseen in the background unless they are being monitored by something similar to Glasswire.
Do not overlook massive usage by devices such as network printers both, wired and wireless, as driver updates among other activities can be very large and under the right circumstances the wireless aspects of a connected printer can allow itself to be used as a "wireless access point" potentially defeating the normal wireless security encryption.
Most Windows based computers can have Glasswire installed on each machine to check usage but other types of measurement may not reflect a true or complete story. Example: Win10's internal usage monitor doesn't consider Windows Update usage to be "usage".
#3: Wireless access.
This is the Big One! The most difficult area and the most likely to be the source of unidentified usage.
> First, is an effective level of wireless encryption enabled? <
If you run an "open wireless network" any and every device that comes within wireless range can and will connect to your network and use data. This would even include the cellphone or other wireless device in the pocket of a visitor.
Do not depend on the usual short range of wireless signals to protect you. Signal radiation patterns and signal strength and directionality can vary greatly due to physical environment and atmospherics.
Secure your wireless network with WPA-PSK at a minimum
With the advent of dual and tri-band routers insure that all wireless frequencies have been encrypted.
> Again be sure that all Guest Accounts have been disabled <
> Again be sure that WPS has been disabled <
> Be very careful of the settings and permissions afforded to wireless printers.<
That brings us to your last question:
"All I'm asking for is a way to view that data myself so I can stop this obscene waste of data!"
The answer to that is this:
Your Router is at the heart of your Network. Every bit and byte of data (other than transmission failures) that is used will go through your Router as well as the Hughes Modem.
Hughes has their "measurement point", Point B.
If you wish to have a counterpoint to that the best spot is your Router itself.
Check your Routers capabilities to see if it offers Traffic Monitoring in some manner.
If not, the most straight forward way to a concrete answer and the greatest control would be to upgrade your Router to one that offers that feature.
I have an Asus RT-AC3100. There are other Asus models that offer the Traffic Analyzer function but read carefully.
The Asus interface details usage by date range, device name and device IP:
It also provides statistical data per device:
If your present Router doesn't offer these features and you are unwilling to upgrade then the only other alternative is to change the wireless encryption passkey on all wireless frequencies so that absolutely no wireless activity can take place. In addition you will need to audit every setting outlined in all categories outlined above in #1 Hardware, #2 Wired and #3 wireless.
At that point generate a new wireless passkey and install it in only a single device ... just one, no more.
Monitor your usage over a period of time. Understand that, that type of activity is sporadic and may take quite some time to reoccur,
Add one device back in at a time, over time. Eventually that activity will reoccur. The more time and the more devices that are added the "fuzzier" the picture of the culprit will be.
Truly the answer lays in having a router that provides the tools you need to monitor and maintain your Network.