Is this something that just started?
Have you tried power cycling your HughesNet equipment? That means unplugging the equipment, waiting about a minute, then plugging it back in and waiting about five minutes before checking to see if the problem is alleviated. I wouldn't power cycle both the HughesNet modem and the ATA at the same time. I'd power cycle the modem, then wait about five minutes and try your phone, and if it's still not working, try power cycling your ATA, then see after that.
The reps are on M-F from approximately 8AM to 5PM EST, so if power cycling the HughesNet equipment doesn't help the reps will help you.
I see it's your first post here, so welcome to the community! I pulled up your account and I see our chat agent has already gotten your HughesNet Voice service working again! Feel free to contact us again if you have any other concerns, we're here to help.