A few years ago I was working with a group of financial advisors and they were subleasing space from another office. This office had an outside tech guy that came in once a month or so. He had them tied in such a way as to make himself indispensable.
But even as he tied them up with his services, he loved to cause difficulties, relished it really. He would spread rumors true and untrue, tried to set departments against one another. He delighted in causing tensions and when called on it denied it all.
At one point one of the advisors I was working with utilized his services. Then he told the advisor that I never paid the invoice. When I confronted him with the advisor, brandishing the cleared check verifying prompt payment, he claimed it must have been a bookkeeping error. I then was able to recommend that he fire his incompetent staff and hire my firm to do the work. But then he would have no ability to falsify claims.
I did this knowing that he or his wife did the books. I also did it in front of the advisor, because he did not believe the complaints against the tech were valid.
This was the beginning of the end for his IT support. Not only did I forever harass him about him needing better accounting support, he received no further work orders from my people and the rest of the office had reached the end of their patience with his chaos as well.
He was eventually replaced with an in-house IT support staff. Had he been competent, qualified and able to work and play well with others, I may have recommended him to others. But that was not the case; I would never recommend him to anyone. No office needs the chaos that this type of evil brings forth.