(1) Where -

(a) calls originally directed to another line are being automatically forwarded to a subscriber’s line as a result of action taken by a third party, and

(b) the subscriber requests his provider of electronic communications services ("the subscriber’s provider") to stop the forwarding of those calls,

the subscriber’s provider shall ensure, free of charge, that the forwarding is stopped without any avoidable delay.

(2) For the purposes of paragraph (1), every other communications provider shall comply with any reasonable requests made by the subscriber’s provider to assist in the prevention of that forwarding.