I vaguely remember some verbiage in Verizon telephone directories stating that if some piece of equipment that is connected to the telephone line causes problems with the network, Verizon would attempt to reach out to the subscriber before suspending services.
I think those terms are standard to most regulated providers, I see the same verbiage here in the current 204/431 Bell MTS directory about disconnecting a customer if their equipment interferes with the system.