Backtime doesn't send password-reset emails yet — resets happen through whoever runs your team's account instead.
If someone else on your team is an owner or admin: ask them to open Team admin (the gear icon inside Backtime), find your name, and click "Reset password." They'll get a link back to send you — opening it lets you set a brand new password.
If you're the owner, or the only person on your team: there's nobody else who can generate that link for you, so reach out directly and we'll get you back in — matthew@gothammediahouse.com.