Given that length of 80 M and assuming that your basic phone is NOT working, that suggests that it is a simple break, in one or other or both wires in the pair; or a short-circuit at that distance.
Assuming your basic phone is working and possibly ADSL, then the distance measured by a JDSU or TDR, should be the distance measured from your house (NTE probably) to the Exchange, which you have indicated is well in excess of 80 M.
There is a very slight chance that your "pair" have been moved into the new Cab 7; but not onward connected to the Exchange.
A TDR, Time Domain Reflectometer is basically a small, specialised RADAR system, designed to measure wire lengths to breaks or shorts - I used one many times on a variety of circuits - Ethernet, general electrical etc.
As TDR did not mean much to my colleagues, I generally referred to it as "my Pocket Radar Set".
Like radar in degree, the TDR sends a pulse down the wires, being reflected at particularly breaks and shorts, with lesser reflections caused by squeezing, tight corners etc.
A JDSU is similar; but adapted specifically for phone systems.
One maker uses both terms in on-line adverts etc.
Edited by eckiedoo (Thu 21-Sep-17 07:41:02)