My email address is incorrect but when I try to edit it I get a message saying the new addresses are

[thommo-19]

When I try to edit my email address I get a message saying the email addresses (tried 2) are already in use. May have other accounts I can't remember ??

[k1ooo-slr-sales]

simple, if you have control over the email addresses that you are being told already have an account then use those addresses to reset the passwords.  You should then find out the user IDs attached to those emails and be able to log in to them once you reset the password.