system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible my ISP is lying about my data usage to force me into paying more?

My family and I are stuck in Alaska with GCI as our ISP, and we are paying $150 a month for 500 GB of bandwidth. We rarely went over out bandwidth until 5 or 6 months ago, and now we are going over constantly, and it is just getting worse. We can buy 70 more gigs for $10 a piece, but even that doesn't last for very long. This month we are already on our 4th "data bucket". That's over 700 gigs in a month. I don't know what is causing it. My parents are old and only use tablets, they occasionally watch netflix or hulu. I have an xbox that used 87 gigs over the last 30 days, and my computer bandwidth monitor is showing significantly less data than  was used.

As far as I can tell, the only things left that could cause this are my smart home devices (4 google home devices), a bad router or modem, or my ISP is screwing us over. Could this be caused by poor wifi signal in a house causing repeated data requests when a packet can't get through or something? I'm really not sure what I should or even can do at this point. It's incredibly frustrating.
gpt
Log into your router to see whether there is a bandwidth monitor in there.  It might show you usage per device.  While you're in there, change your wifi password.  

If it doesn't show usage per device, but does show total usage, then use a process of elimination by unplugging devices for a day or two at a time.