Here's a suggestion ...
start to build up a reputation for being unavailable
phone battery dies (smartphones are great for this

)
put your phone offline during meetings (you can even get an app to do it automatically)
in the bathroom, left the phone on your desk
can't hear ringing in the MTR
put the phone on silent during a meeting, forget to turn it back on
... etc ...
of course, the best excuses are the ones SHE uses when you try to call her and can't get through (ain't it funny how it's not OK for you to be unavailable, but it's totally ok for her to be uncontactable?)