How can I determine what my data usage is on my gateway and my priority rank?

if you have the Nokia gateway you can see your usage since the last boot up on the “Status” page – http://192.168.12.1/web_whw/#/status. I don’t think there’s a way to see that on the Arcadyan.

Your monthly statement will show the total usage for the billing period. You have to download the "Detailed Bill" to get the daily usage breakdown.

There isn’t supposed to be a cap, but they will likely shut anyone down using massive data.

I believe that Home internet is always the lowest priority regardless of how much data one has used.