In 25 years of practice I have never experienced this. Finally decided to fire a difficult client (drama, late on compensation, non-payment for late cancellations and verbally abusive)and now she is threatening to ruin my career by writing about me on the internet among other things. Does anyone have any experience with this or advice????
This has not happened to me but I can only imagine how it made you feel
Personally, I would not give her another thought, although I would check YELP and if she does write a nasty review you can respond to it in a neutral manner.
Other than that, you are doing the best thing by getting rid of her nastiness.