got the account verification e-mail but when i try to sign in/reset password my username is not recognized
Could you please elaborate on the issue? Are you talking about your account on support.mozilla.org?
Sorry, I thought it had been posted on the subforum on Firefox sync. It's when I try to sync that I encounter this issue.
Did you set up the account on a device that asks you to pair a device? If so, this is the older version of sync.
Are you using an email address in the username? https://accounts.firefox.com/reset_password