I was once a Hughesnet customer and had the same problems from time to time.
It is shared bandwidth; therefore, the more devices added, the less bandwidth you receive. It's a normal practice for Hughesnet to "oversell" available bandwidth.
I've also known quite a few people with the service and they all report the same problems. Once their 30 day trial period ends and their contracts are locked in, the service they receive after that point is poor to say the least. It's as if they give new customers "PRIORITY" access until the trial ends, and then, BAM, customers find out exactly what they're paying for.
You are not alone! There are thousands upon thousands of complaints filed against Hughesnet for their business practices.