I have had the same issue for the last fortnight, I have no dial tone and anyone who tries to call just gets an engaged tone. I've tried the diagnostics test on the website and it just gets stuck at 99%. I've tried to call from a mobile but after a few minutes in the queue, I've had to put the phone done as the 0845 numbers cost too much on a mobile. I'm getting no where online.
I have checked your line and it's coming back as blocked so before I'm able to arrange for a technician I would just like to confirm whether you have tried a different handset just to eliminate any equipment fault?