I had a sudden spike of data usage, roughly 30g, and according to customer service it was an android device showing it was used up in an hour time span. We have no android devices and how could that much data be used in an hour? We have no gaming devices and only one smart TV.
If you give us permission we can check your usage and try to get more details on that 30GB spike.
One possibility is that your smart TV is powered by Android, and it could have downloaded something.
If you think there might be someone with unauthorized access to your network, you can also try to change your password. Here is a tutorial on how to do that: How to change your Wi-Fi name and/or password