I received an invitation from my organization administrator, created a public account, and used the token to connect. However, my account is still public so I can't log on to Arc Pro or access organization data on ArcGIS Online. How do I convert my public account to an organizational account? In MyESRI it shows that I am connected to the organization.
Did you see this screen during the process?
If you created a new public account immediately before joining, then there aren't any maps/apps that will be added to the new organization when joining. For this reason, you could create a new account to join and not miss out on transferring in your old content.
A few other things to try that you may have already:
If all of these troubleshooting steps fail, I would recommend your administrator getting in touch with Esri Support and creating a case so an analyst can take a closer look at the issue.
I hope this helps,