I've been an active member on this community for quite a while
You've been a member with the kabum21 account since May 30, 2018. That's hardly "quite a while" IMO, although you did manage to earn merits from some of the most respected members for
a single post you made. Somehow. I think they were being overly generous, but everyone has different standards.
The reason you're looking for is here, and you quoted it yourself:
You have been permanently banned by a forum moderator, probably due to spam or plagiarism.
My guess is you plagiarized something, and I'm also fairly certain someone will show up with the evidence of that.