Help with wiring Eircom phone socket

Hi,

Would anyone be able to help with the wiring setup on an Eircom phone socket used for broadband. The inside circuit board has the name "CSI/Austin Taylor Communications". In the top left-hand corner are two slots labeled L1 & L2 where the telephone wire pushes into. This does not make a great connection and sometimes the wires come loose. (This may account for the variable connections speeds I have been getting in the last few months). In the bottom right-hand corner are three screw-down connectors labeled L1, R, and L2. Can I use these connections instead as I imagine they would give a better connection than the slot connectors. Incidently, the phone wire used to wire the 2 phone sockets in my house is white twisted bellwire. Is this ok to use? They come down through an internal stud partition wall and I would prefer not to have to replace it!