Data usage

We have been with cox for over a year, just recently we moved and noticed DAta overage,  We have called 3 times and keep getting excuses that make NO sense to me, I am disabled with brain stem compression, so maybe I am not comprehending how this data is used/works?  we have only 1 tv has firestick/sling,  1 laptop  and 1 phone using the wifi.   first they said maybe a hacker?? really?? I dont think so,   Maybe who they are currretnly using to calculate their data is shady???  is there a class action suit?  What really makes NO sense is, we decided to test this, and when we were over 2900 Miles away, NOT in the home  NOT using tv   phone or laptop, it still showed  5gb,  10gb  17 gb  32 gb  used etc.  HOW in the world do u explain this?   Password was changed  etc.   They claimed  , oh,  the modem must detect your Tv, computer and phone  even if ALL are not in use and are turned off!!!???  so , you mean we are charged for data, EVEN when we are NOT using it??? help someone email me and clarify this  , I have been now taking the firestick off the tv when itsoff, and taking battery out my phone,   so the modem/data doesnt get used, but it is still taking data!!! so nothing makes sense. except their data reported on usage is bogus.  How can use data when NO one in house and all devices are removed from the house???? only tv was in house but not in use.