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????
No, they usually fired themselves if things did not go the way they thought it would or should in their point of view.
Very stressful and potentially hurtful for your business. As others have mentioned as well, you have been in business for a long time and had not complaints to speak of. I would not worry and let this person go.
Maybe take a look at Michael Port’s book: Book yourself solid. In particular his red rope policy.