For advisors, firing a key tech vendor can be a risky venture. The consultant could behave totally unethically or, in worse still, find a legitimate way of socking it to you.
This post contains some good advice to keep you from acting emotionally in the heat of a dispute with a tec vendor.
But the key peice of advice is never to be too dependent on any one consultant or vendor.
Always plan your breakup even as you just begin your honeymoon.