It's a bug bounty kind of thing because I found a critical bug and told you about it. The fact that you asked me to doesn't change that fact. It just means the bug was even more critical. It had caused you to shut the betting down while you attempted and failed to find it. I have asked about why I didn't get the bounty in the past. You laughed and refused to answer.
Seems like this is the crux of the argument. He asked you for a favor, you did it expecting to get paid. Can the two of you see each other's side? Do you think Dean was trying to screw you over, or can you see that he was asking a peer for assistance? Can Dean see that you were hurt that something that he's compensated others for, he didn't think to compensate you for?