Support for Support

Hi,

I'm trying to post an update to a previously posted support request but can't. At the bottom of the page at https://premium.wpmudev.org/forums/topic/cookie-question?replies=1#post-330283 it has a join button instead of a comment form, but I'm already a member.

How do I post updates to my support requests'?

Thanks,
Vernon

In all my 20+ years on the internet I've never needed support for getting support!