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It goes like this.
I have one final task to solve before starting in a new job at a different company. This guy, which is also a board member in the company in which I'm currently hired, is also an IT consultant and project manager in a fairly large company. This said person is also a key person for me being able to solve this last issue. I send him a complete guide on what he has to do before I can move on and wrap it all up.
First conflict arises because he doesn't follow the guide and tells me something is not working. I kindly inform him why and the response I get is very personal and not kind in any way, telling me and my boss that I am bad at my job and that he will bill us for 1000 USD for the 5 hours he used "debugging" and testing. This should have taken him 30 minutes and I have no idea what he spent those 5 hours doing.
It comes down to that my boss sides with this asshole and tells me that I have to do the task all over and test the system for the 4th time (yes I tested it 3 times beforehand to make sure nothing could go wrong) What my boss and the asshole doesn't know is that my uncle is vice president in the firm the asshole is working for. After kindly reminding this asshat that he has to follow the guide and that I can confirm everything is working, he keeps on attacking me. It's very rare that I fuck up and I have consulted 2 colleagues and got them to test it as well. They found no issues at all. The asshole ignored my request of documentation that something was not working.
I'm so full of being treated as an idiot so I send my uncle the email correspondence with the asshole to confirm that this is not how any of their employees should behave independant of my ability to do my job.
He will speak with this fucker tomorrow at work as first thing in the morning. I'm not proud of the way I went about this, but that was like the last drop, if you know what I mean.
Sorry for the long rant.