Deleting your account permanently removes everything Ghostly stored on its server for you: your account, your pets, their stats, their interaction history, your token balance and streak, and the record of which devices you used. It cannot be undone. The ghost on your phone is not affected.
If you no longer have the app, email cvs.devs01@gmail.com from the Google account you signed in with, subject "Delete my Ghostly account". We delete the data within 7 days and confirm by reply.