With automatic billing, the funds are withdrawn on the same day that the new bill is created. The due date is for those who are on invoice billing. If you are on automatic billing, but the funds are not being withdrawn as they should, you should post in the myAccount and Billing section about that issue.
I believe you can prepay, but I'm not sure how. @BirdDog might know how, as I believe I've seen him talking about it. He may reply since I tagged him.
I'm not sure about pre-paying for tokens.
When someone has an issue and they post about it on the Facebook page, a lot of times they're asked to PM, they're assigned a case manager that will call them, or their asked to post here. Not all posts are addressed, but Facebook isn't much geared toward support. Then again, not all posts need to be addressed, and for various reasons.
That's @Gwalk900 who has posted some guidance before. I do believe you have to be on the invoice billing plan to pay in advance though.
The default payment method employed by HughesNet is "Auto-Pay".
It is possible to pay ahead, that is to say that you will show a positive credit balance ..... however ......
If you have "invoice billing" you have 30 days to make your payment from the data that the bill is generated. If you have "Auto-Draft" your payment method will be charged the micro-second that your bill is generated.
If you were to pre-pay and are on "Auto-Draft" you run the very real risk your payment method getting a double hit as the Auto-Pay is .... automatic.
Be aware the Invoice Billing usually comes with a $5.00 monthly charge.
But .... you can pay early ... just watch the details.
My bill is generated on the 5th of the month. I pay online as a"one time" payment and hence show a credit balance: