Hi,
Since you were able to delete the agents, you also have to delete the lien. The steps to do so can be found here.
- Get the lien name by using “gcloud alpha resource-manager liens list”
- delete the lien with “gcloud alpha resource-manager liens delete <LIEN_NAME>”
From there, you should be able to safely delete the project as per our docs[2].
I hope this is useful to you.