I created a project a few months ago while playing around with leaderboards and achievements. Wasn't sure whether I wanted them or not.
In the end I deleted the project off of the Google Developers Console and released my app without leaderboards or achievements.
I now want to add leaderboards and achievements to my app but get the classic Client ID is globally unique error. So I went into the Google Developers Console and tried to restore the old project but am getting an error message stating
"You do not have permission to perform this action. Only project owners may delete or rename a project."
Yet I am the project manager.
What can I do?
I figured it out. The new console is bugged and would not allow me to restore a project. I used the old console and had no problem restoring my project and can now use everything properly. No need to change package or keystore. :D