Current clients: your instance will be hosted under the same terms (with no instance management panel) until your balance goes below zero or it is migrated to another host. You can manage it with tickets or by e-mail (support at maastodon dot net).
Anyone else: MaaStodon is closed. Feel free to contact if you need an instance managed, would like to buy MaaStodon or software, or want to discuss any other project that we may help with.