Unsure if this location is correct for this question, but not finding any other location which seems to address the problem.
Have forgotten user name. Tried two likely suspects, inputting them with correct email address, but get no email to reset password.
Tried to create a new account with each of the likely passwords; error message informs that each is "in use".
What next?
If you're sure the account exists under one of the user names you tried (you can check on Special:ListUsers to confirm) and you're sure that it's your account, then not receiving a password reset email means the email on the account is not set to the email address you think it is, or there is no email on the account. In any case, I'm not sure if staff will help to recover the account (I would suggest to ask on the support desk for more help with this in general), so the general advice is probably going to be to just create a new account. (As far as that goes, I may be wrong, but I don't think MediaWiki checks for duplicate passwords, so it doesn't make sense that it would complain about a password being in use when you try to create an account... are you sure it wasn't complaining about the chosen username or the email address you entered?)
