Data use spike - no explanation

Any number of things can cause a spike in data usage. Even if there was no change in HOW you use data. I watch netflix, and one month watched, (Binged actually), "The Blacklist":. I found out later, that that TV series is in 4K which used about 8GB an hour, versus the normal 2.4-2.8 gb an hour that regular HD shows use. You can use the Cox App on your cell phone to pull up the data usage or login to https://www.cox.com/internettools/data-usage.html and you can pull up the data usage, look at history and more. Also, remember some devices do backups to the cloud, that can use a LOT of data. If you have a gaming system, like a PS4/5 or xbox, they can use a lot of data when they update. and if you use a streaming device, and you turn off the tv, without turning off the streaming device, it could still be trying to stream, even if you aren't watching the tv. Last but not least, some amazon devices, echo/dot will start listening/ and trying to identify what you are saying, even if you aren't talking to it, but it's a tv, and THAT can use a bit of data as well. First stop would be to look at the history and see what days you used a lot of data and then see if you can identify what may have been going on, on those days.