Marketplace support pages on https://marketplace.concretecms.com/ are currently broken. This problem has been present since at least 7 November, possibly failed as far back as 3 November (when the PRB review system exhibited a similar issue). Portland Labs has been notified.
Posts appear to hang. They have actually posted, but the process does not complete and update the page. After posting a support request, if you wait a few seconds then refresh the page the post or new support thread will be shown.
The developer will not receive a notification of your support request (likely a consequence of 1)
When the developer replies to a support request, 1 & 2 above will also affect their post, so you will not be notified.
Temporary workround - try sending the developer an email or PM to alert them of your support request.