why is my admin superuser on node not existing?

Okay so i have a huge problem with a deadline. Im in my final year and i had to do a final year project to graduate. The thing is i could have done it myself, but with all the secondary assignments and projects to also give us to do, i gave a remote developer to do it for me in nodejs. i understand nodejs alot, but ive never encountered this problem. He just gave me back the system and the database. i checked the database and got the email for the admin superuser and tried logging in, but its not working. its saying “email doesnt exist”, so its not that the password is incorrect, the email doesnt exist according to the database. but its the same database i got the admin email. so my question is that how can i be accessing the same database that my system uses and trying the same admin email of the system inside the database but its telling me that the email doesnt exist. is it a problem with my laptop or something else? its a superuser so obviously it is only one so how can it not be existing? im working on a deadline so fast answers would be appreciated.