Probably the usual thing, plagiarism. Even if it isn't that, your posts are all typical bounty hunter shitposts, and on top of that I suspect you either bought or hacked the account. You posted mainly in the altcoin mining section up until
Sept. 3, 2018 and the
next post after that was on Oct. 25, 2018 and was a bounty application. That wouldn't get you banned, though.
Didn't the ban PM tell you what the reason was?