Although the Reps won't be back on until tomorrow to be able to answer the callback problem, have you run a modem isolation test?
I'm assuming you have by your reference to trying all of the usual methods, but just thought I'd ask in case you hadn't.
Also, have you tired Glasswire for your Windows based PCs?
It would be best to start a new post for your particular issue. With that said, and you can answer it on the new post if you like, do you have a satellite TV receiver that could be connecting to the service?
"Last couple of months I've had unusual and unexplained data loss"
Then we need to investigate.
"My Smart Browsing indicator is not showing I am using smart browsing"
We then need to make sure that you know under what circumstances SmartBrowse would become active and why it would at times become inactive .... that is to say that an actual FAP condition is in effect.
" I sent a message and got a reply that someone would contact me from support within 24 hours. However I never got the call"
Sadly this is not all that unusual but we do have to look at what they would have likely done:
Your past posting history in the Community shows that you have had ongoing issues with running into FAP.
In truth the data can only be consumed in two places ... on the Hughes end of your connection or on your end of your network.
They (support) would have likely started addressing the issue by ruling the Hughes equipment in or out by having you perform a modem isolation test:
If the results of the test indicated that data was used during the period that all of your equipment was disconnected then your case would be escalated to repair or replace the Hughes equipment as required.
If the result of the test is negative then we have to conclude the "something" on your network is consuming the data. The question the becomes "who".
Here is where the news gets a little ugly.
Hughes is your ISP. They deliver Internet services to the point of the Modems LAN port.
They are NOT a personal computer/software repair service.
What software you have installed, what the OS's and individual software settings are is anyone's guess.
If you choose to share your Internet connection with other devices, again that is YOUR choice, your Network and your responsibility.
The more devices you have, the more complex the problem becomes.
Hughes simply can not do more than to perhaps offer some general suggestions or perhaps a referral to a paid 3rd party IT service.
Hughes supplies you with a connection. What and how you "spend" that connection is your responsibility.
A single computer has 65,536 com ports. If you have a browser open you know it ... you can "see" the program open and it uses port 80. If you are running an email client program like Outlook or Thunderbird you are using two ports, one for incoming and another for outgoing mail. Again no surprise as you can see the open program.
What you can't see in the normal sense is all of the background processes that turn on, do their job and hopefully turn off.
Here are the "applications" running on my Win7 machine ... those, I can "see":
Now lets look at the background processes running:
A whopping 100 of them currently
That leaves a lot of the 65,536 unmonitored, unseen.
The above is on a single computer.
What of my other 10 computers plus two tablets, the wife's iPad, our two iPod touches and a networked printer ?
There are troubleshooting steps we can take to find the culprit but frankly, it isn't Hughes's "job" to do "repairs" on your devices and your network.
That is the first hurdle you need to get past.
As said earlier there are procedures that we can employ to track this down but you have to be willing to participate in a "guided" process.
There are a few volunteers here in the Community (including myself) that can guide you through the process but you have to be willing to follow steps.
Those steps start with the Modem Isolation Test outline in the beginning.