I also have no dial tone on the line (tested on the test socket as well as the faceplate socket)
Assuming you expect the telephony service to be working, i.e. to receive a dial tone, then there is a line fault. In Openreach-speak, you have a "one leg dis". A broadband service will continue to operate, with severely degraded speed, with one wire of the pair disconnected.
Just report a telephony fault to whoever provides your service (don't mention anything related to your broadband service). Once the pair is remade whole, your broadband service will recover.