I can see that Studio One 3 Professional has been activated on your account.
When you are logged into Studio One, simply go to the menu Studio One > Studio One Activations. Use the drop down and select "Show my existing Product Keys".
Select your Studio One 3 Professional Key. Studio One will close and reopen. Then you will have access to Studio One 3 Professional and all content.
If after doing this, you still don't see Studio One 3, go to your My.Presonus.com account and submit a support ticket.