You;re updating Windows with mobile data and think you can't use ore than 10 GB a month? What other uses are you doing that you think should use more than 10 GB-30 GB a month? But yes a bad connection that makes your PC constantly resend the packets of data will of course use more data. Obviously you must live in an area with poor reception so perhaps a change of carrier is needed. Just as one would do with any carrier where reception is an issue.

You said you would have gone with another service. What service would that be? If you are using Homefusion you obviously do not have access to cable or DSL internet. Because no one with cable or DSL access would use mobile data as their main internet connection. So that leaves satellite. Now if you think Homefusion is bad go read up on Hughesnet and Wildblue.