HI @roland.smart and my apologies for the late follow-up!
I would recommend merging your Pantheon.io account with your other account; you should easily be able to this following these steps but if you run into trouble feel free to reach out to our support team, they will be able to assist you!
Note that once you merge your account using the Okta login, you will be required to use Okta to login into your account via mobile too!
Hope this helps; please let me know if you have any follow-up questions!