While a person can stream with HughesNet, it's not made for cord cutting, or streaming on a regular, every day basis, as the data will run out to quickly, especially if the streaming is done in HD rather than SD or LD.
Do you stream every day, and did you tell them that you would be streaming every day? If so, and it's been no more than around 90 days since your sales call, you can request a sales call review to determine whether appropriate expectations were set by the sales rep. If it's determined that the sales rep did, in fact, misinform you, you may have recourse regarding the Early Termination Fee if you choose to cancel the service. You can request a sales call review by starting a new topic in the "myAccount and Billing" section. You can click here to start the new topic.
When you say it has been "cutting in and out of service all month long", can you be a little more specific? Do you mean you're actually losing connection to the satellite, and if so, what are you seeing or experiencing that is suggesting this? Or, do you mean you're losing your WiFi connection to the modem?
Regarding your bill, do you know what the $31 is for? If not, you can sign onto the HughesNet MyAccount site, click on My Bill under the My Account tab, and view your latest invoice. In the popup, scroll to the bottom and click on View Site Details on the bottom left. This will give you a full breakdown of your bill. If the charge occurred after your last invoice, you can click on Account History on the My Bill page to see what the charge is for. Still, I'm sure a rep will reply and discuss the billing issue, and possibly in private through a PM, though they will let you know that they've PMed via a reply here. The reps are on M-F from approximately 8AM-5PM EST, and they usually reply within a day or two.