What / how would you tell a 'consulting company' that you want to stop using their services?

I have a contract with ABC Consulting. ABC was bought by XYZ Consulting - and my (ABC) consultant quit once XYZ bought the company.

FACTS:
I don't want to deal with a new consultant.
I don't want to work with XYZ.
I don't like XYZ's 'new way'
The ABC Consulting contract I signed didn't have any TERMINATION CLAUSE - therefore I can TERMINATE if I want to.


Amazingly, XYZ is trying to FORCE ME TO CONTINUE the contract.

What would you say to XYZ to leave me alone?

We are upset and surprised that you would threaten us, your former client, in an effort to FORCE US TO CONTINUE AGAINST OUR WILL with your company. Your contract does not require us to continue because it does not have any clause that 'forces' us to stay.

Proper business etiquette and common sense should cause you to allow us to stop services... as no quality consulting company forces its customers to stay when they don't want to.

We signed the contract with ABC, and your services and consultants are totally different than ABC.

By threatening us you are acting in an extremely unprofessional way. We will not be forced to work with a 'consulting' company, and according to our lawyer we will not only win a court case, but we will sue you for our costs and damages. Finally, we will go to our contacts in the media to express our dissatisfaction with your actions, and will enjoy seeing your name appropriately sullied in your market place. Driving you out of business would be a service to all companies.