Sounds perfectly reasonable for customers to be cut off from a service if they deliberately or through ignorance (despite attempts to teach them which are obviously being made) cause problems with that service.
It's no different from people being cut off from 911 calls who repeatedly make fake calls as a joke (why it would be funny to place fake calls to an emergency service is beyond me, but there are people who think it's hillarious to see the police screaming through the street every day to non-existent emergencies at their neighbours' addresses).