No one meant any disrespect, nor is anyone calling you a liar. They are saying that you are "embellishing" which means adding details to make a story seem more than it is. It's very human, especially in situations that invoke strong emotions. You clearly felt a negative emotion with what happened, and with that I can sympathise. However, I also recognize that in your situation it seems that you didn't inform the person in question of your "crew rules".
Which is quite essential if your rule is as important as "we don't turn in treasure" because that's a (if not the) core component of the game. You can't expect players to immediately understand what you were doing. You tried communicating with them, they tried communicating with you. Something went wrong there. And then, this player did something that, in your eyes, is wrong. However, you still got rewarded for your initial effort. So, in the end, what is the problem? That a player did something you didn't want (something essential to the game), despite you getting a positive thing from it ? That's not a breach of the Pirate Code, my friend.
Putting that aside, it is always a shame to see a player who has been active on the forums for a long period of time leave. However, as someone who has been around for a long time, I thought you would have made peace with your situation after having had a chance to speak with Rare about it. As a longstanding member of the community, you should know that Rare is a reputable game developer who takes instances of griefing/misbehaviour very seriously. They will have looked into this, especially if it regards a person who represents them.
I hope you can make peace with your situation, and I wish you all the best.
