Hi MeaganG2
I'm sorry to hear about the inconvenience you're facing with managing multiple logins. When changing the email address and it's already been used by another user, you may receive an error message saying "There is already a user with this email. Enter a different email". If this is not the error message you received, you can change your email address by going to my.MYOB or you can also check the link here for more information. Don't hesitate to drop us a post again if there's anything you need assistance with.
Best regards,
Doreen