Whether you pay or not the car will have the capability and it will dutifully ask the home server what it should do. Toyota will still be able to see exactly where you, what you're doing, and be able to unlock/start your car whenever they want. you just won't be able to.
I don't know how serious you are, but the modern LTE antennas are really small and are tightly integrated. Very difficult to remove without severely damaging the system.
