It can take (sometimes hours) for the plugin to register your purchase. Please be patient and give the plugin time. You could try logging in and out of your account. Worst case scenario is it just isn't working, or you might have entered the wrong username, in which case you'd contact [email protected] (email) regarding your problem, and see if they can help. Allow time with them also, they're busy.
Due to the time this was posted, you should be unbanned if not i would consider emailing [email protected] or asking one of the head-staff if it's worked please tag a mod to close this.
but a ban is a punishment, and you gotta work for it or wait 1 months or 2 to get unbanned. Trust me there are worse things than a Minecraft ban lmao