Hello, we had full fibre installed 17th september .the engineer told us that the phone would work in next 12 hours.It didn't,as we are both in mid80s a landline phone is a priority as there is virtally no signal so cannot telephone for help.
Welcome to this user forum for BT Residential phone and broadband customers.
Is your phone plugged into the green socket on the back of the BT Smart Hub 2, as shown below?
If connected as @Keith_Beddoe diagram and still not working, first try a reboot of the hub.
If still not working check that DV has been configured by entering 192.168.1.254 in your browser's address bar to access the hub manager and look to see if the phone symbol shows your number or 'not configured'.
If 'not configured', you will need to contact customer services 0330 1234 150