She says she was threatened by you. She insist you threatened
her. So be it. Although you are puzzled by it.
Most likely you did not meant it, or even aware of it. But she
perceived as such. As far as she is concerned, you did
threatened her. OK, so apologize to her, tell you did not meant it.
Keep it simple, do not try to elaborate, like I elaborate here.
Just say sorry, you didn't realize you threatened her. Full
stop.
The next move is hers, for her to accept your apology and
forgive you. If she don't, then dump her. She is not friendship
material.
Don't let her blackmail you too. You just need to say sorry.
Don't let her extract a compensation from you. If she does,
dump her too. She is not worth your friendship.
But if she accepts your apology, freely without condition, you
may give her a gift.