Hi, I am in exactly the same boat as yourselves.
After receiving caller display for years and years with no problems mine just stopped working back in September last year.
I reported it and they have sent out many different engineers, they have asked me to try a new phone and wires which I have done and still not receiving it.
I have complained more times than I can remember I have wasted hours on the phone repeating checks that I have previously done many times, I have taken time off work to make sure someone in when engineer calls, I have had engineers cancel on me at the last minute, engineers not turn up at all.
I have been asked to be patient and it will be working within the next couple of days, had faults closed without it being fixed, received text messages saying the fault is now fixed and now 8 months later still no further forward.
I am so frustrated that today I have told them if it is not fixed within the next 14 days I will seek legal action, contact the telecommunications ombudsman and the national newspaper.
Have you had any sucess with yours?
Yes, have done that, have taken off faceplate and plugged phone directly into test socket. Also got a brand new phone and tested with that in case it was the appliance. BT have admitted it is their end but keep telling me it will be fixed within a couple of days. 8 months later and I am still waiting. I read on here somewhere that theirs went off when infinity was being installed in the area, from what I believe the same is happening in my area but I can't be sure as I live 3 miles out of town so never see anyone from BT working. Does anyone know if this could this be the cause of it?