Posts on here often involve the forum team enabling/disabling the caller ID setting on your connection to try to reactivate it. Official replies on here can take up to a week and are not guaranteed.
You can try phoning the support number again and the general advice seems to be to try at 08:00 when it is likely to be less busy.
If you are minded to try any further investigations yourself, you could ask a neighbour, friend, family member if you can test one of your phones on their line. This will confirm caller ID is showing OK on that phone.
Having done that, try the known working phone into your main/master socket and with no other phone devices plugged into extensions.
If you still have no caller ID then you will at least have tried all the steps you can reasonably do yourself. If you find the phone starts to receive caller ID doing the test above, then you may have some other kind of line issue.
Probably worth continuing to call the telephone support no. whilst waiting for a reply on here so as to cover both bases.
Thanks for posting on the community forums - welcome!
I'm sorry to hear that your caller display has recently stopped working, this is slightly strange. Have you been able to get any help with this since posting? I have tried to take a look at the status of your landline service, but for some reason your landline status is showing as 'not contactable' which may be part of the issue.
Are you having any other problems with your landline service at all?