Probably what I would do is call 811 (Tennessee's locate service,
1-800-351-1111). Inform them that you plan on digging up the broken
support cable anchor as pole itself does not appear to be in service
as the lines are all sagging.
When a locate is done, the underground lines are all marked, of
course, but also any oddities are noted and passed on to the owners of
the various utilities. The nice thing about Tenn811 is that you don't
have to worry about trying to navigate the various ownerships of the
infrastructure as they know. Most states have a similar "one call,
call before you dig" number.
As a side note, once the locate is done and any unmarked cables
actually laying on the ground are free game for "accidental mowing"
when you are in your approved dig dates. However, any marked cables
that you do destroy will result in a hefty fine and repair fees.
Up here, we have to deal with damage from firearms.
Themed Olympus Photo Exhibition: http://www.tope.nl/