Have you made any attempt at finding the cause of your data loss ?
The normal procedure is to start off with a LAN disconnect test:
This will determine if the Hughes Modem is using data on its own. If no data is used during the testing period then we can only conclude that something on your network is using the data.
Well Hughes should make it so these large updates are not counted
Why ? Data is data. Hughes has no connection to Microsoft.
You choose to "upgrade" to Win10. There was more than ample warning on many websites including this one that Win10 does not offer more than just token control over updates along with the fact that it shares "telemetry" with Microsoft. That "feature" right there will use even more of your data.
Its all about making informed decisions, not about ISP's and capped data plans.
I tried a couple of the Win10 Preview versions, found it lacking in many respects that include lack of control and privacy concerns.
I stayed with Win7 on some of my computers and went to Linux on a couple more.
You had choices. If you can't make your OS stay within the bounds of your service plan, then you likely chose poorly.