Beginner Gardening: Letter from neighbor about my yard -what to do?, 3 by thegardenofevil

thegardenofevil wrote:
The neighbor behind my back wall sent me this letter: " I was wondering if you could please trim your trees, shrubs, and creeping ficus from the back wall. We have been paying to maintain them but my husband passed away and I can no longer continue to do this. Thanks, --Pat"

There is a 10' slope on my side up to that back wall. Beyond the wall is level ground with her pool and 2-story house with a balcony. Our lots are typical small California suburban lots, so her house is fairly close, and the plants along the wall give my privacy that I don't want to lose- privacy not just while I'm in the yard, but through 7 back windows (including a wall-of-windows in family room). Also, I would have to pay someone to do the work as I am in my late fifties with a leg problem and can no longer climb the slope.

POLL: Is it my responsibility to keep plants from going over the wall? What would you do?

PHOTOS:
1) My yard with slope and plants and trees in front of back wall
2) Another angle of my approx. 10' wide slope
3) Composite of neighbor's yard, taken over the wall in 1998 when I had no shame (It's only my 2nd house, I had just moved in and wanted landscaping ideas. )