After you have filled out the form on https://wechange.de/cms/bigbluebutton/ you will receive two emails from us: one email in which we confirm that we have activated BBB for you and send you some information about it, and an email with the invoice. You simply pay the invoice in the traditional way within 14 days.
Even if you have set up a Pay-As-You-Like post, the post will not collected through this method. Payments for BBB and Pay-As-You-Like run independently of each other.