Such an array of helpful hints, brilliant thread.
On a more serious note, OP you could obtain a cheap sim, or even a free one, stick it in your mobile, send her a text along the lines of.. Dear Kelsey, please believe me when I say I've deliberated over sending this text, we are close and I would never hurt you, but I have to say this for your own benefit (and ours), so please accept it in the way it's meant. GET A FUCKING WASH YOU DIRTY MANKY COW.
Lots of love, ??
Then just throw the sim away, that should be the end of it, unless she kills herself and police trace the vicious cruel texter, then you're in the shit.
here to help.