If you haven't, I'd suggest opening a ticket in their helpdesk to contest it. If the banning moderator responds, ask for it to be escalated to SoftwareReview. A permanent ban for that post seems ridiculous, especially since you have nothing to gain monetarily. (It's a free plugin!!) Maybe you should have mentioned that you wrote the plugin for full disclosure, but a perma ban for that seems absurd.. unless there were other reasons involved in their decision.
Here's my suggestion to everyone who participates on WHT:
1. Follow their rules.
2. If you feel you've been unjustly targeted or given an infraction because of a post, open a ticket in their helpdesk and contest it. (I have opened a ticket every time I received an infraction, and have had one reversed)
3. If you see other people self promoting or not following the rules, report those posts. (I have reported posts made by our competitors for self-promotion, and their posts have been removed)
The moderators at WHT believe they are enforcing the rules fairly. In most cases, they probably are, but because of our competitions long history and position in the market they are favored.
WHT even promoted a thread for one of our competitors beta release announcements. They have never given us the courtesy.
Things are changing, but it takes time. We're going to do all we can do, and continue to make Blesta better.
Don't be intimidated, if you have something to say, say it! Just make sure you follow the rules.