Updates, streaming, downloading programs. It's actually possible to use 10 GB in a couple of hours. If you are a direct customer (not via Dish, DTV, etc...) you can see more detailed usage information using ESVT. https://myesvt.exede.net/
You can also email your account information to email@example.com or call customer service at 855-463-9333 and, they can tell you how the data was used.
There can be many many things that can cause that. I will gladly review it with you. Things like Windows 10 updates have been a MAJOR factor. So lets review it, send an email to firstname.lastname@example.org and we can see what went on