ADSL socket not working?

[#1]

when i got my fibre set up BT, after hours of complicated faffing, fitted a new box which has an ADSL and telephone socket box combined.  I have a primary ADSL socket in another room which I now can't get to because of a fitted wardrobe. the current adsl cable that is connected via that socket to the router is damaged therefore i want to use the secondary socket BT set up but when i plug the router in it there is no network connection.  i'm not sure if i am doing something wrong or if the connector doesn't actually work.  that wouldn't surprise me as they took half a day with two people to connect me up
Any advice would be appreciated.  Many thanks.

[#2]

I think the reason that secondary socket won't work is because it is a filtered socket. When the engineer fitted the new master socket, any telephone extension wiring would have been connected to the filtered output of the master socket (making these extensions only suitable for telephones).
If the socket behind the wardrobe was previously working as a modem connection point with the new master socket, then it must be an unfiltered socket.
What can you do to fix this? One potential option is that if the secondary socket is wired directly back to the master socket, you could wire it into the unfiltered (AB) terminals of the master socket. This would mean that you could then connect your modem to that socket. You could not connect a phone directly to it, although you could potentially connect a phone to it with a microfilter. That would kind of defeat the idea of having only one filter at the master socket, but it is possible.
One thing to be aware of is that if the secondary socket uses older cable, or flat cable, it is not ideal for carrying VDSL2 (fibre) signals, as there may be some signal loss. You would need to try it to see how it performs.
Best of luck.

[#3]

Hi ok the engineer that comes to install the Fibre service is also supposed to install a modem to the new master socket that you had fitted which gets the signal from the fibre cab the router is connected to the modem via a ethernet cable so you can get online.
so am i right in guessing no modem was installed ?  

[#4]

thanks for responding guys.  we had a modem fitted to the cable/socket upstairs and then a second adsl socket/box was fitted downstairs which also has the telephone attached.
i'm afraid i'm not techie 😕