If you are too high out of your mind to read the big RED warning message, maybe you shouldn't be purchasing narcotics online. Had this user tested a deposit before? Reusing addresses is stupid but the problem here lies almost entirely with the user. The blatant lies in the header of the post accusing of scamming etc are probably what got him banned.
Anyways, not a shill, I don't trust carders but I would trust them over someone who can't read a big red warning..
The issue has nothing to do with whether the OP made a mistake or not. He clearly did. They could have said "tough luck, you fucked up, we can't help you." The issue is that instead of saying that, alphabaysupport "offered him a gift on his 2.9 BTC back in exchange for him deleting his reddit thread" That is the definition of extortion and shows that AlphaBay's support team cannot be trusted. Then they banned him from the market completely for "disrespecting AlphaBay". This is not how a professional market's support team should behave.