When having an extension built my builder removed my NTE5. he replaced it after the build was completed, however my nternet works but my landline does not. the phone displays a message saying check the landline lead. since the internet is working, could this be a simple case of crossed wires?
No, polarity is irrelevant. However, did he connect the wires to the correct terminals. Is it a single socket with an external filter or a filtered faceplate with separate sockets for phone and broadband?