False Case

I was involved in a relationship with a girl, which started 6 years ago. During our relationship, we used to talk over the phone and met each other, but never had sex. She prompted me many times to sexually engage with her but I denied. One day she was kidding me of not having sexual desires and challenged me to make a " sexually vulgar phone-call asking her to come to me for sex on the next day ". I did the same being unaware of her intention. I ended this relationship 2 years ago when I came to know her relationship with many other men. Now I am going to be appointed on a government post and she has threatened me to marry her otherwise face a case of "sex on False Promise of Marriage" on the basis of some intentionally recorded phonecalls - one of which is my vulgar phone-call to her, which I have already mentioned and the rest contain normal talk. I too have evidences of her relationship with many other men. Please tell me how I can defend me.