Your full email address, such as name@rr.com.
Use the reset option on the sign-in page and choose a new password you have not used elsewhere.
Yes. It keeps working and is managed through your Spectrum account.
Clear the cache, pause browser extensions, or try a different browser.
Yes. Sign in through your phone browser, or add the account to a mail app with your full address and password.
Use a long, unique password, keep it private, and ignore emails that ask you to confirm account details.