Hopefully this link provides the answer you are looking for.
If your not getting the answer from the link then call the broadband team.
As I am not a NOW broadband customer I can’t be much more help I’m afraid.
NOW Broadband customers can get in touch anytime between 8am–11pm.
Thanks, I did & I'm still waiting for their solution.
The very helpful Irish girl called me back the next day and said that their tech's were "having problems with their system" - a catch-all excuse for a multitude of reasons why they can't stop my phone service being misused in my absence.
Its a newly refurbished holiday let that I put NOWTV WiFi into as the previous Vodafone proved unreliable.
Maybe I'll just cut the wires to the sockets - Simples!