Thank you for reaching out to us in our community and welcome, sorry to hear caller display has stopped working on your handset, I have been able to locate your account with the details we have for you and everything at our end is as it should be, regarding caller display, have you been able to try a different phone with caller display to see if the phone is at fault?
Thanks for your reply. I have now tried using another phone with caller display, namely a Gigaset (instead of Panasonic). The caller display is still not displaying the caller's number. It just says "external call"