I just wanted to add to the above great advice to look at this as pure "business"...keep the emotions, anger, etc in check...hard in check. You're a businessman Sunny, try to treat it as as former customer taking you to court or something like that...she knows you and how to push your buttons, don't let her do that.
In the depths of winter, I finally learned that within me there lay an invincible summer. - Albert Camus
Uncertainty is the very condition which impels people to unfold their powers.-Eric Fromm