Getting logged out even though I have a paid account

not letting me assign any users, says I have zero licenses, which is not true, as I have a paid in full subscription to workplace pro license as the owner.

First - you can check how many Pro licenses you have in Account management > Billing

Then if you go to User management > Users, there should be something like blue link visible and if you click it, then there will popup a window with your available/used licenses.

If used are 0, then this means you haven't assigned any license to users. If that's the case, then follow the article from previous post.
Otherwise - you should probably open a ticket and contact Zoom support:
Submit a request – Zoom Support