When your HughesNet is back on, you'll need to run some speed tests to begin troubleshooting your speed issue. The instructions for those tests are here. Please be sure to read through the instructions thoroughly before running any of the tests, as tests run improperly won't be of value. After you've run some tests you should start a new topic in Tech Support about the speed issues and post your testmy.net "My Results" page URL so that the test results can be viewed. You can start a new Tech Support topic here.
As for data issues, there is a test that can be performed to determine whether there is a data leak, and there are steps that can be taken to help your devices use as little data as possible on their own. This would also be addressed in Tech Support, and in the same topic as your speed issues, if you like.
When it comes to billing, the HughesNet reps will have to help you with this. They're on M-F from approximately 9AM to 6PM EST, though there is occasionally one on during the evening. You'll likely see a reply from one tomorrow.