It is the old false dialling prefix scam, enables you to book box office films as the receiver tests for the phone line to be connected, but then cannot call back to make the charge periodically. Just a different (and easier) version of the 9v battery trick.
Problem is that the card/box runs out of credit and that is the end of PPV, unless that is you remove the false dialling prefix and let it phone home, you can then pay up and look big.
A very old scam which resurfaces every six months, it also doesn't work if you have never subscribed (obviously) and doesn't work if the box has not been connected to a phone line.
