Which NOW telephone number did you use to reach out the NOW Broadband Team ?
Did you use the telephone number in this screen shot below or a different number ?
i find that ringing the NOW Broadband Team between 8am to 9am is the best time to call them, where usually i get through pretty quickly, where phoning them throughout the day or evening varies depending how busy the helplines are.
Then try the telephone number on this link below, which will get you through to a NOW Broadband Team member (don't worry the link says complaints it will get you through to the NOW Broadband Help Desk).
Don't know if the time getting through will be an improvement or not.