No free seats appear after payment
10 hours have passed and nothing has changed
Have you tried to use the Check for un-synced users button?
There are such users, but they are not active
Maybe double check how you are assinging licenses.
The best way is to simply activate/deactivate users on Flow/ShotGrid and not do this via the Autodesk Identity backend as that is more cumbersome and can lead to users being assinged a license but not active on the site.