Any ideas how you got into this odd situation? DB Import?
Before you do anything - make sure you have a backup
You’re probably going to have to use an SSH console / terminal…
SSH into the server and run the following one line at a time:
./launcher enter app
su - postgres
psql -d discourse
This will get you to the “PSQL interactive terminal” where you can execute queries.
Something like this will display the details of the two accounts:
SELECT id, username, created_at, last_seen_at FROM users WHERE email = 'firstname.lastname@example.org';
(make sure you include the semi-colon on the end)
Here is where you are going to want probably report back what you see.
To exit the SQL console type:
\q and press enter.