The only test for data leaks is a Modem Isolation Test. This will determine whether a data leak is on HughesNet's end or on your network. Being that the modem must be left on after the test and until the reps have a look at the data, it's usually best to run the test overnight Sunday/Monday when it's the weekend. The instructions are as follows...
Please perform the following test outlined in the graphic below, though follow the full instructions written below the graphic. This is known as a Modem Isolation Test, and it will help to determine whether the issue is with HughesNet or your local network..
1: Disable the WiFi in the HT2000W modem.
2: Take a screen capture of the HughesNet Usage Meter, along with the clock on your computer screen.
3: Disconnect the LAN cable from the modem, noting the date and time of disconnect.
4: Leave the LAN cable disconnected from the modem for several hours. HughesNet recommends doing this overnight, or during the day while at work. DO NOT unplug the modem from the power. The modem must remain powered.
5: Reconnect the LAN cable to the modem, noting the date and time of reconnect.
6: Take a screen capture of the HughesNet Usage Meter, along with the clock displayed on your computer.
7: Post your screenshots to the community.
Do not unplug, power cycle or internally reboot the modem after the test has been run, as the reps need to be able to reconcile your modem data logs with what is shown in the screenshots. Any of those three things will wipe out those logs, rendering the test results moot. Only after the reps have responded with their findings should any of those three things be done.
Please be aware that, if you downloaded any large files just prior to this test, some usage may appear to have occurred due to the slight delay in the modem reporting the data usage to the server, but it should be rather negligible.
If you don't know how to disable the WiFi in the HT2000W, please see "How do I manage my built-in WiFi modem?" in this PDF. Please be sure to click "Save Settings" after unchecking "SSID Enable" for each of the four tabs individually (2.4Ghz, then 2.4Ghz Guest, then 5Ghz, then 5Ghz Guest).
I only have my smart phone to do this testing. Will I be able to do this on my phone.?
Unfortunately, no, as the WiFi has to be disabled during the test. Once you disabled it with your phone you'd no longer be able to connect to turn it back on, and you'd only be able to do so with a LAN cable connected device.
If you can tell us what devices you use with the service we may be able to tell you where to look or even what apps/programs to use to monitor the data usage on a particular device, as it's very likely that the drain is actually one or more of your devices using data without you being aware of it, or even more data than you're aware of. This is practically always the case, though finding it is sometimes the tricky part. Just in case a device is connected that you've forgotten about or perhaps aren't aware of, you can see what devices are and were connected since the last time the modem was plugged in on this page.
And when I say "what devices you use" I don't mean specifics. You don't have to divulge that. Just basics, like "A Roku device, an Android phone, a Windows 10 laptop, an Android tablet, an iPhone", for arbitrary examples.
Without a LAN cable connectible device you can't run the test. It can't be run using your phone.
However, if your phone is the only device you have connected to and use with HughesNet, that's where to look for the data issues.
You may want to install Glasswire on the phone, as well. It will tell you not only how much data the phone is using, but what processes, programs and activities are using it, and just how much with each.
If you don't already have it, you should also install the HughesNet Mobile App and check your WiFi signal, as a weak signal can cause higher data usage due to dropped data packets during the WiFi transmission. You can get it from Google Play.