Does your landline telephone work
from the same socket as the broadband? (Using the phone socket of a filtered faceplate or dangly filter, whichever is the case).
You have the symptom of one wire of the pair being disconnected, which results in very low connection speed on broadband and a dead phone. Seeing as you have just been doing things to the wiring you may have disconnected one you shouldn't.
Edit: Oops

, it must as you've done a Quiet Line test. But was it from the same socket, and which socket has the broadband - the master or an extension?
My broadband basic info/help site -
www.robertos.me.uk. Domains, site and mail hosting -
Tsohost.
Connection - AAISP Home::1 80/20. 200GB. Sync 72313/12530Kbps @ 600m. BQMs -
IPv4 &
IPv6
Edited by RobertoS (Sun 01-Oct-17 18:18:43)