Gradually all the Goodies' utility services are discontinued, including the telephone (they cannot go out to pay the bills). Then, later, when the nation is in the grip of poverty, the BBC cuts back their services by 100%, and the ending of television broadcasts means that the Goodies are cut off entirely from the outside world.
The Goodies' utility services are progressively withdrawn, including their phone service (they cannot venture out to settle their accounts). Subsequently, during a time of widespread poverty, the BBC drastically curtails its services, and with television broadcasts ceasing, the Goodies become entirely isolated from the outside world.