Setting up your connection
Having a Fibre to the Node, Fibre to the Node, or ADSL connection will require your connection to be set up like the picture below.
Testing an alternative phone socket
It's always best to try your modem's connection to a different phone socket (if available) for testing. Move your equipment to each phone socket in your home and wait 5 minutes to see if the connection comes online. You should also try an alternative phone cable where possible, and remove any filters or splitters that might be part of your connection.
Has this fixed your internet?