I've had a recent spat of problems wherein Verizon techs showed up
to perform service on the NID through which my (old A)DSL line runs
and managed to disconnect me in a variety of ways (couldn't figure
out which white went with which color... which is a bit excusable, I
guess, because it's old style 5-pair with no stripes on the whites;
mismatched pairs 26 and 27 on a 50-pair block; corrected the error
on the 50 pair block after I'd worked around the problem, without
also correcting the wiring I'd changed). Note that I'm a bit more
prone to these sorts of problems as I live in an apartment... though
that also means there's a better chance I don't have to hike up a
telephone pole under cover of darkness to fix things.
If it's this sort of problem, no software logging will help; go to
Radio Shack and pick up a telco toner and linesman's headset (that
is, a beige box) and go fix it yourself. Waiting for Verizon to
come back and fix their error takes weeks...