If your phone line has a constant engaged tone, or no dial tone at all, then there may be a fault somewhere on the line or in the exchange. For Voip this could be the phone not registering, SIP ALG on your firewall could be preventing this. The phone may not be allocated to a user if you have not spoke to the support desk.
Firstly you need to check your internal equipment. Try the phone line with another handset just to rule out that your handset isn't broken. This does not apply for VoIP.
If you also check that all of your internal wiring and hardware is not faulty by plugging your phone directly into the master sockets test socket. On the master BT socket you can detach the faceplate with two screws, under here is a phone connector. If your phone works when you plug your handset into the test socket, there is a problem with some of your internal wiring i.e phone cable, phone, micro filter, cable extensions.
If your phone still does not have a dial tone or is fully engaged when plugged into the test socket, this is a fault only a BT engineer can fix.
If you do not have an analogue phone and we have given you VoIP, Please ensure the phone is connected to the internet and allow it to boot up, It should go though some firmware updates and then get allocated a user.
Please report this to our support team at [email protected] or 03332025000 if the issue persists.