Thank you for reaching out to us. Currently, it appears some customers are experiencing a similar issue when attempting to make payments online while logged in. It is currently being worked on by our engineering team and should be resolved within the next few weeks or less. In the meantime, I recommend logging out of your account then clicking on the "Pay now" option at the top of the support center home page. This will bring you to a page where you will have to type in your account information. If this doesn't work, you can make a one-time payment over the phone by calling 866-347-3292.
In regards to your service, I apologize for the experience you are having. It appears your equipment is fully operational and receiving adequate speeds currently. It seems the Roku device you have connected uses the most data on average. While you may not be using your devices often, they do pull large amounts of data over time when in use. I recommend taking advantage of your Bonus Zone from 2 AM to 8 AM. You do not need to be awake for this, but it is recommended to schedule any downloads or updates for this period of time since you normally have most of this data remaining each month.