Hi @Anonymous User
Are you an existing NOW Broadband customer ?
If so go to My Account > My Broadband & Calls on here and under Messages see if there is an early email sent by NOW with regards to your NOW Broadband order confirmation where somewhere on the email there will be an indication of a telephone number allocated to your landline.
You could also check all your NOW related emails on your email address in box for any NOW Broadband confirmation that your NOW Broadband order was processed & accepted.
Or alternatively give the NOW Broadband Team a call (use the telephone number on this link below where i am assuming you have a mobile to phone them).
Or drop them a message using the web form found on the same link page below.