Xfinity Connect through their website. But I am sure what that has to do with anything. I got emails from Comcast that told me my password change was sucessful, but I didn't request a password change, until I couldn't sign in after getting this email (which was sent to my gmail account). This happened twice in just ten minutes.
I have received emails from Comcast telling me my password was successfully changed, but that change didn't come from me. And sure enough, attempting to sign in fails. I had to request a password reset, changed my password, and minutes later, someone changed it AGAIN, and AGAIN I couldn't sign in.
Keeps happening to me too. I was thinking my kids were doing it until they were sitting in front of me eating and it happened. I downloaded the Xfinity Authenticator App so that anyone that tries to sign in as me has to be approved from my phone but I don't know how that will work if they're just resetting the password. Besides, what are they trying to do with my password and access to my account?!